Database Solutions

DATABASE SOLUTIONS (2nd Edition) THOMAS M CONNOLLY & CAROLYN E BEGG SOLUTIONS TO REVIEW QUESTIONS Chapter 1 Introduction- Review questions 1. 1List four examples of database systems other than those listed in Section 1. 1. Some examples could be: †¢A system that maintains component part details for a car manufacturer; †¢An advertising company keeping details of all clients and adverts placed with them; †¢A training company keeping course information and participants’ details; †¢An organization maintaining all sales order information. 1. 2Discuss the meaning of each of the following terms: (a)dataFor end users, this constitutes all the different values connected with the various objects/entities that are of concern to them. (b)database A shared collection of logically related data (and a description of this data), designed to meet the information needs of an organization. (c)database management system A software system that: enables users to define, create, and maintain the database and provides controlled access to this database. (d)application program A computer program that interacts with the database by issuing an appropriate request (typically an SQL statement) to the DBMS. (e)data independenceThis is essentially the separation of underlying file structures from the programs that operate on them, also called program-data independence. (f)views. A virtual table that does not necessarily exist in the database but is generated by the DBMS from the underlying base tables whenever it’s accessed. These present only a subset of the database that is of particular interest to a user. Views can be customized, for example, field names may change, and they also provide a level of security preventing users from seeing certain data. 1. 3Describe the main characteristics of the database approach.Focus is now on the data first, and then the applications. The structure of the data is now kept separate from the programs that operate on the d ata. This is held in the system catalog or data dictionary. Programs can now share data, which is no longer fragmented. There is also a reduction in redundancy, and achievement of program-data independence. 1. 4Describe the five components of the DBMS environment and discuss how they relate to each other. (1)Hardware:The computer system(s) that the DBMS and the application programs run on. This can range from a single PC, to a single mainframe, to a network of computers. 2)Software:The DBMS software and the application programs, together with the operating system, including network software if the DBMS is being used over a network. (3)Data:The data acts as a bridge between the hardware and software components and the human components. As we’ve already said, the database contains both the operational data and the meta-data (the ‘data about data’). (4)Procedures:The instructions and rules that govern the design and use of the database. This may include instructions on how to log on to the DBMS, make backup copies of the database, and how to handle hardware or software failures. 5)People:This includes the database designers, database administrators (DBAs), application programmers, and the end-users. 1. 5Describe the problems with the traditional two-tier client-server architecture and discuss how these problems were overcome with the three-tier client-server architecture. In the mid-1990s, as applications became more complex and potentially could be deployed to hundreds or thousands of end-users, the client side of this architecture gave rise to two problems: †¢A ‘fat’ client, requiring considerable resources on the client’s computer to run effectively (resources include disk space, RAM, and CPU power). A significant client side administration overhead. By 1995, a new variation of the traditional two-tier client-server model appeared to solve these problems called the three-tier client-server architecture. This new arc hitecture proposed three layers, each potentially running on a different platform: (1)The user interface layer, which runs on the end-user’s computer (the client). (2)The business logic and data processing layer. This middle tier runs on a server and is often called the application server. One application server is designed to serve multiple clients. (3)A DBMS, which stores the data required by the middle tier.This tier may run on a separate server called the database server. The three-tier design has many advantages over the traditional two-tier design, such as: †¢A ‘thin’ client, which requires less expensive hardware. †¢Simplified application maintenance, as a result of centralizing the business logic for many end-users into a single application server. This eliminates the concerns of software distribution that are problematic in the traditional two-tier client-server architecture. †¢Added modularity, which makes it easier to modify or replace o ne tier without affecting the other tiers. Easier load balancing, again as a result of separating the core business logic from the database functions. For example, a Transaction Processing Monitor (TPM) can be used to reduce the number of connections to the database server. (A TPM is a program that controls data transfer between clients and servers in order to provide a consistent environment for Online Transaction Processing (OLTP). ) An additional advantage is that the three-tier architecture maps quite naturally to the Web environment, with a Web browser acting as the ‘thin’ client, and a Web server acting as the application server.The three-tier client server architecture is illustrated in Figure 1. 4. 1. 6Describe the functions that should be provided by a modern full-scale multi-user DBMS. Data Storage, Retrieval and UpdateAuthorization Services A User-Accessible CatalogSupport for Data Communication Transaction SupportIntegrity Services Concurrency Control Servic esServices to Promote Data Independence Recovery ServicesUtility Services 1. 7Of the functions described in your answer to Question 1. 6, which ones do you think would not be needed in a standalone PC DBMS? Provide justification for your answer.Concurrency Control Services – only single user. Authorization Services – only single user, but may be needed if different individuals are to use the DBMS at different times. Utility Services – limited in scope. Support for Data Communication – only standalone system. 1. 8Discuss the advantages and disadvantages of DBMSs. Some advantages of the database approach include control of data redundancy, data consistency, sharing of data, and improved security and integrity. Some disadvantages include complexity, cost, reduced performance, and higher impact of a failure.Chapter 2 The Relational Model – Review questions 2. 1Discuss each of the following concepts in the context of the relational data model: (a)relati on A table with columns and rows. (b)attribute A named column of a relation. (c)domain The set of allowable values for one or more attributes. (d)tuple A record of a relation. (e)relational database. A collection of normalized tables. 2. 2Discuss the properties of a relational table. A relational table has the following properties: †¢The table has a name that is distinct from all other tables in the database. †¢Each cell of the table contains exactly one value. For example, it would be wrong to store several telephone numbers for a single branch in a single cell. In other words, tables don’t contain repeating groups of data. A relational table that satisfies this property is said to be normalized or in first normal form. ) †¢Each column has a distinct name. †¢The values of a column are all from the same domain. †¢The order of columns has no significance. In other words, provided a column name is moved along with the column values, we can interchange c olumns. †¢Each record is distinct; there are no duplicate records. The order of records has no significance, theoretically. 2. 3Discuss the differences between the candidate keys and the primary key of a table. Explain what is meant by a foreign key. How do foreign keys of tables relate to candidate keys? Give examples to illustrate your answer. The primary key is the candidate key that is selected to identify tuples uniquely within a relation. A foreign key is an attribute or set of attributes within one relation that matches the candidate key of some (possibly the same) relation. 2. 4What does a null represent?Represents a value for a column that is currently unknown or is not applicable for this record. 2. 5Define the two principal integrity rules for the relational model. Discuss why it is desirable to enforce these rules. Entity integrityIn a base table, no column of a primary key can be null. Referential integrityIf a foreign key exists in a table, either the foreign key value must match a candidate key value of some record in its home table or the foreign key value must be wholly null. Chapter 3 SQL and QBE – Review questions 3. 1What are the two major components of SQL and what function do they serve?A data definition language (DDL) for defining the database structure. A data manipulation language (DML) for retrieving and updating data. 3. 2Explain the function of each of the clauses in the SELECT statement. What restrictions are imposed on these clauses? FROMspecifies the table or tables to be used; WHEREfilters the rows subject to some condition; GROUP BYforms groups of rows with the same column value; HAVINGfilters the groups subject to some condition; SELECTspecifies which columns are to appear in the output; ORDER BYspecifies the order of the output. 3. What restrictions apply to the use of the aggregate functions within the SELECT statement? How do nulls affect the aggregate functions? An aggregate function can be used only in the SEL ECT list and in the HAVING clause. Apart from COUNT(*), each function eliminates nulls first and operates only on the remaining non-null values. COUNT(*) counts all the rows of a table, regardless of whether nulls or duplicate values occur. 3. 4Explain how the GROUP BY clause works. What is the difference between the WHERE and HAVING clauses? SQL first applies the WHERE clause. Then it conceptually arranges he table based on the grouping column(s). Next, applies the HAVING clause and finally orders the result according to the ORDER BY clause. WHERE filters rows subject to some condition; HAVING filters groups subject to some condition. 3. 5What is the difference between a subquery and a join? Under what circumstances would you not be able to use a subquery? With a subquery, the columns specified in the SELECT list are restricted to one table. Thus, cannot use a subquery if the SELECT list contains columns from more than one table. 3. 6What is QBE and what is the relationship between QBE and SQL?QBE is an alternative, graphical-based, ‘point-and-click’ way of querying the database, which is particularly suited for queries that are not too complex, and can be expressed in terms of a few tables. QBE has acquired the reputation of being one of the easiest ways for non-technical users to obtain information from the database. QBE queries are converted into their equivalent SQL statements before transmission to the DBMS server. Chapter 4 Database Systems Development Lifecycle – Review questions 4. 1Describe what is meant by the term ‘software crisis’.The past few decades has witnessed the dramatic rise in the number of software applications. Many of these applications proved to be demanding, requiring constant maintenance. This maintenance involved correcting faults, implementing new user requirements, and modifying the software to run on new or upgraded platforms. With so much software around to support, the effort spent on maintenan ce began to absorb resources at an alarming rate. As a result, many major software projects were late, over budget, and the software produced was unreliable, difficult to maintain, and performed poorly.This led to what has become known as the ‘software crisis’. Although this term was first used in the late 1960s, more than 30 years later, the crisis is still with us. As a result, some people now refer to the software crisis as the ‘software depression’. 4. 2Discuss the relationship between the information systems lifecycle and the database system development lifecycle. An information system is the resources that enable the collection, management, control, and dissemination of data/information throughout a company. The database is a fundamental component of an information system.The lifecycle of an information system is inherently linked to the lifecycle of the database that supports it. Typically, the stages of the information systems lifecycle include: pla nning, requirements collection and analysis, design (including database design), prototyping, implementation, testing, conversion, and operational maintenance. As a database is a fundamental component of the larger company-wide information system, the database system development lifecycle is inherently linked with the information systems lifecycle. 4. 3Briefly describe the stages of the database system development lifecycle. See Figure 4. Stages of the database system development lifecycle. Database planning is the management activities that allow the stages of the database system development lifecycle to be realized as efficiently and effectively as possible. System definition involves identifying the scope and boundaries of the database system including its major user views. A user view can represent a job role or business application area. Requirements collection and analysis is the process of collecting and analyzing information about the company that is to be supported by the d atabase system, and using this information to identify the requirements for the new system.There are three approaches to dealing with multiple user views, namely the centralized approach, the view integration approach, and a combination of both. The centralized approach involves collating the users’ requirements for different user views into a single list of requirements. A data model representing all the user views is created during the database design stage. The view integration approach involves leaving the users’ requirements for each user view as separate lists of requirements. Data models representing each user view are created and then merged at a later stage of database design.Database design is the process of creating a design that will support the company’s mission statement and mission objectives for the required database. This stage includes the logical and physical design of the database. The aim of DBMS selection is to select a system that meets th e current and future requirements of the company, balanced against costs that include the purchase of the DBMS product and any additional software/hardware, and the costs associated with changeover and training. Application design involves designing the user interface and the application programs that use and process the database.This stage involves two main activities: transaction design and user interface design. Prototyping involves building a working model of the database system, which allows the designers or users to visualize and evaluate the system. Implementation is the physical realization of the database and application designs. Data conversion and loading involves transferring any existing data into the new database and converting any existing applications to run on the new database. Testing is the process of running the database system with the intent of finding errors.Operational maintenance is the process of monitoring and maintaining the system following installation. 4. 4Describe the purpose of creating a mission statement and mission objectives for the required database during the database planning stage. The mission statement defines the major aims of the database system, while each mission objective identifies a particular task that the database must support. 4. 5Discuss what a user view represents when designing a database system. A user view defines what is required of a database system from the perspective of a particular job (such as Manager orSupervisor) or business application area (such as marketing, personnel, or stock control). 4. 6Compare and contrast the centralized approach and view integration approach to managing the design of a database system with multiple user views. An important activity of the requirements collection and analysis stage is deciding how to deal with the situation where there is more than one user view. There are three approaches to dealing with multiple user views: †¢the centralized approach, †¢the view integration approach, and †¢a combination of both approaches.Centralized approach Requirements for each user view are merged into a single list of requirements for the new database system. A logical data model representing all user views is created during the database design stage. The centralized approach involves collating the requirements for different user views into a single list of requirements. A data model representing all user views is created in the database design stage. A diagram representing the management of user views 1 to 3 using the centralized approach is shown in Figure 4. 4.Generally, this approach is preferred when there is a significant overlap in requirements for each user view and the database system is not overly complex. See Figure 4. 4 The centralized approach to managing multiple user views 1 to 3. View integration approach Requirements for each user view remain as separate lists. Data models representing each user view are created and then mer ged later during the database design stage. The view integration approach involves leaving the requirements for each user view as separate lists of requirements.We create data models representing each user view. A data model that represents a single user view is called a local logical data model. We then merge the local data models to create a global logical data model representing all user views of the company. A diagram representing the management of user views 1 to 3 using the view integration approach is shown in Figure 4. 5. Generally, this approach is preferred when there are significant differences between user views and the database system is sufficiently complex to justify dividing the work into more manageable parts.See Figure 4. 5 The view integration approach to managing multiple user views 1 to 3. For some complex database systems it may be appropriate to use a combination of both the centralized and view integration approaches to managing multiple user views. For examp le, the requirements for two or more users views may be first merged using the centralized approach and then used to create a local logical data model. (Therefore in this situation the local data model represents not just a single user view but the number of user views merged using the centralized approach).The local data models representing one or more user views are then merged using the view integration approach to form the global logical data model representing all user views. 4. 7Explain why it is necessary to select the target DBMS before beginning the physical database design phase. Database design is made up of two main phases called logical and physical design. During logical database design, we identify the important objects that need to be represented in the database and the relationships between these objects.During physical database design, we decide how the logical design is to be physically implemented (as tables) in the target DBMS. Therefore it is necessary to have selected the target DBMS before we are able to proceed to physical database design. See Figure 4. 1 Stages of the database system development lifecycle. 4. 8Discuss the two main activities associated with application design. The database and application design stages are parallel activities of the database system development lifecycle. In most cases, we cannot complete the application design until the design of the database itself has taken place.On the other hand, the database exists to support the applications, and so there must be a flow of information between application design and database design. The two main activities associated with the application design stage is the design of the user interface and the application programs that use and process the database. We must ensure that all the functionality stated in the requirements specifications is present in the application design for the database system. This involves designing the interaction between the user and the data, w hich we call transaction design.In addition to designing how the required functionality is to be achieved, we have to design an appropriate user interface to the database system. 4. 9Describe the potential benefits of developing a prototype database system. The purpose of developing a prototype database system is to allow users to use the prototype to identify the features of the system that work well, or are inadequate, and if possible to suggest improvements or even new features for the database system. In this way, we can greatly clarify the requirements and evaluate the feasibility of a particular system design.Prototypes should have the major advantage of being relatively inexpensive and quick to build. 4. 10Discuss the main activities associated with the implementation stage. The database implementation is achieved using the Data Definition Language (DDL) of the selected DBMS or a graphical user interface (GUI), which provides the same functionality while hiding the low-level DDL statements. The DDL statements are used to create the database structures and empty database files. Any specified user views are also implemented at this stage.The application programs are implemented using the preferred third or fourth generation language (3GL or 4GL). Parts of these application programs are the database transactions, which we implement using the Data Manipulation Language (DML) of the target DBMS, possibly embedded within a host programming language, such as Visual Basic (VB), VB. net, Python, Delphi, C, C++, C#, Java, COBOL, Fortran, Ada, or Pascal. We also implement the other components of the application design such as menu screens, data entry forms, and reports.Again, the target DBMS may have its own fourth generation tools that allow rapid development of applications through the provision of non-procedural query languages, reports generators, forms generators, and application generators. Security and integrity controls for the application are also impleme nted. Some of these controls are implemented using the DDL, but others may need to be defined outside the DDL using, for example, the supplied DBMS utilities or operating system controls. 4. 11Describe the purpose of the data conversion and loading stage.This stage is required only when a new database system is replacing an old system. Nowadays, it’s common for a DBMS to have a utility that loads existing files into the new database. The utility usually requires the specification of the source file and the target database, and then automatically converts the data to the required format of the new database files. Where applicable, it may be possible for the developer to convert and use application programs from the old system for use by the new system. 4. 2Explain the purpose of testing the database system. Before going live, the newly developed database system should be thoroughly tested. This is achieved using carefully planned test strategies and realistic data so that the entire testing process is methodically and rigorously carried out. Note that in our definition of testing we have not used the commonly held view that testing is the process of demonstrating that faults are not present. In fact, testing cannot show the absence of faults; it can show only that software faults are present.If testing is conducted successfully, it will uncover errors in the application programs and possibly the database structure. As a secondary benefit, testing demonstrates that the database and the application programs appear to be working according to their specification and that performance requirements appear to be satisfied. In addition, metrics collected from the testing stage provides a measure of software reliability and software quality. As with database design, the users of the new system should be involved in the testing process.The ideal situation for system testing is to have a test database on a separate hardware system, but often this is not available. I f real data is to be used, it is essential to have backups taken in case of error. Testing should also cover usability of the database system. Ideally, an evaluation should be conducted against a usability specification. Examples of criteria that can be used to conduct the evaluation include (Sommerville, 2000): †¢Learnability – How long does it take a new user to become productive with the system? Performance – How well does the system response match the user’s work practice? †¢Robustness – How tolerant is the system of user error? †¢Recoverability – How good is the system at recovering from user errors? †¢Adapatability – How closely is the system tied to a single model of work? Some of these criteria may be evaluated in other stages of the lifecycle. After testing is complete, the database system is ready to be ‘signed off’ and handed over to the users. 4. 13What are the main activities associated with oper ational maintenance stage.In this stage, the database system now moves into a maintenance stage, which involves the following activities: †¢Monitoring the performance of the database system. If the performance falls below an acceptable level, the database may need to be tuned or reorganized. †¢Maintaining and upgrading the database system (when required). New requirements are incorporated into the database system through the preceding stages of the lifecycle. Chapter 5 Database Administration and Security – Review questions 5. 1Define the purpose and tasks associated with data administration and database administration.Data administration is the management and control of the corporate data, including database planning, development and maintenance of standards, policies and procedures, and logical database design. Database administration is the management and control of the physical realization of the corporate database system, including physical database design and implementation, setting security and integrity controls, monitoring system performance, and reorganizing the database as necessary. 5. 2Compare and contrast the main tasks carried out by the DA and DBA.The Data Administrator (DA) and Database Administrator (DBA) are responsible for managing and controlling the activities associated with the corporate data and the corporate database, respectively. The DA is more concerned with the early stages of the lifecycle, from planning through to logical database design. In contrast, the DBA is more concerned with the later stages, from application/physical database design to operational maintenance. Depending on the size and complexity of the organization and/or database system the DA and DBA can be the responsibility of one or more people. . 3Explain the purpose and scope of database security. Security considerations do not only apply to the data held in a database. Breaches of security may affect other parts of the system, which may in turn affect the database. Consequently, database security encompasses hardware, software, people, and data. To effectively implement security requires appropriate controls, which are defined in specific mission objectives for the system. This need for security, while often having been neglected or overlooked in the past, is now increasingly recognized by organizations.The reason for this turn-around is due to the increasing amounts of crucial corporate data being stored on computer and the acceptance that any loss or unavailability of this data could be potentially disastrous. 5. 4List the main types of threat that could affect a database system, and for each, describe the possible outcomes for an organization. Figure 5. 1 A summary of the potential threats to computer systems. 5. 5Explain the following in terms of providing security for a database: authorization; views; backup and recovery; integrity; encryption; RAID. AuthorizationAuthorization is the granting of a right or privilege t hat enables a subject to have legitimate access to a system or a system’s object. Authorization controls can be built into the software, and govern not only what database system or object a specified user can access, but also what the user may do with it. The process of authorization involves authentication of a subject requesting access to an object, where ‘subject’ represents a user or program and ‘object’ represents a database table, view, procedure, trigger, or any other object that can be created within the database system. ViewsA view is a virtual table that does not necessarily exist in the database but can be produced upon request by a particular user, at the time of request. The view mechanism provides a powerful and flexible security mechanism by hiding parts of the database from certain users. The user is not aware of the existence of any columns or rows that are missing from the view. A view can be defined over several tables with a user being granted the appropriate privilege to use it, but not to use the base tables. In this way, using a view is more restrictive than simply having certain privileges granted to a user on the base table(s).Backup and recovery Backup is the process of periodically taking a copy of the database and log file (and possibly programs) onto offline storage media. A DBMS should provide backup facilities to assist with the recovery of a database following failure. To keep track of database transactions, the DBMS maintains a special file called a log file (or journal) that contains information about all updates to the database. It is always advisable to make backup copies of the database and log file at regular intervals and to ensure that the copies are in a secure location.In the event of a failure that renders the database unusable, the backup copy and the details captured in the log file are used to restore the database to the latest possible consistent state. Journaling is the process of keeping and maintaining a log file (or journal) of all changes made to the database to enable recovery to be undertaken effectively in the event of a failure. Integrity constraints Contribute to maintaining a secure database system by preventing data from becoming invalid, and hence giving misleading or incorrect results. EncryptionIs the encoding of the data by a special algorithm that renders the data unreadable by any program without the decryption key. If a database system holds particularly sensitive data, it may be deemed necessary to encode it as a precaution against possible external threats or attempts to access it. Some DBMSs provide an encryption facility for this purpose. The DBMS can access the data (after decoding it), although there is degradation in performance because of the time taken to decode it. Encryption also protects data transmitted over communication lines.There are a number of techniques for encoding data to conceal the information; some are termed irreve rsible and others reversible. Irreversible techniques, as the name implies, do not permit the original data to be known. However, the data can be used to obtain valid statistical information. Reversible techniques are more commonly used. To transmit data securely over insecure networks requires the use of a cryptosystem, which includes: †¢an encryption key to encrypt the data (plaintext); †¢an encryption algorithm that, with the encryption key, transforms the plain text into ciphertext; †¢a decryption key to decrypt the ciphertext; a decryption algorithm that, with the decryption key, transforms the ciphertext back into plain text. Redundant Array of Independent Disks (RAID) RAID works by having a large disk array comprising an arrangement of several independent disks that are organized to improve reliability and at the same time increase performance. The hardware that the DBMS is running on must be fault-tolerant, meaning that the DBMS should continue to operate even if one of the hardware components fails. This suggests having redundant components that can be seamlessly integrated into the working system whenever there is one or more component failures.The main hardware components that should be fault-tolerant include disk drives, disk controllers, CPU, power supplies, and cooling fans. Disk drives are the most vulnerable components with the shortest times between failures of any of the hardware components. One solution is the use of Redundant Array of Independent Disks (RAID) technology. RAID works by having a large disk array comprising an arrangement of several independent disks that are organized to improve reliability and at the same time increase performance. Chapter 6 Fact-Finding – Review questions 6. Briefly describe what the process of fact-finding attempts to achieve for a database developer. Fact-finding is the formal process of using techniques such as interviews and questionnaires to collect facts about systems, requiremen ts, and preferences. The database developer uses fact-finding techniques at various stages throughout the database systems lifecycle to capture the necessary facts to build the required database system. The necessary facts cover the business and the users of the database system, including the terminology, problems, opportunities, constraints, requirements, and priorities.These facts are captured using fact-finding techniques. 6. 2Describe how fact-finding is used throughout the stages of the database system development lifecycle. There are many occasions for fact-finding during the database system development lifecycle. However, fact-finding is particularly crucial to the early stages of the lifecycle, including the database planning, system definition, and requirements collection and analysis stages. It’s during these early stages that the database developer learns about the terminology, problems, opportunities, constraints, requirements, and priorities of the business and t he users of the system.Fact-finding is also used during database design and the later stages of the lifecycle, but to a lesser extent. For example, during physical database design, fact-finding becomes technical as the developer attempts to learn more about the DBMS selected for the database system. Also, during the final stage, operational maintenance, fact-finding is used to determine whether a system requires tuning to improve performance or further developed to include new requirements. 6. 3For each stage of the database system development lifecycle identify examples of the facts captured and the documentation produced. . 4A database developer normally uses several fact-finding techniques during a single database project. The five most commonly used techniques are examining documentation, interviewing, observing the business in operation, conducting research, and using questionnaires. Describe each fact-finding technique and identify the advantages and disadvantages of each. Exa mining documentation can be useful when you’re trying to gain some insight as to how the need for a database arose.You may also find that documentation can be helpful to provide information on the business (or part of the business) associated with the problem. If the problem relates to the current system there should be documentation associated with that system. Examining documents, forms, reports, and files associated with the current system, is a good way to quickly gain some understanding of the system. Interviewing is the most commonly used, and normally most useful, fact-finding technique. You can interview to collect information from individuals face-to-face.There can be several objectives to using interviewing such as finding out facts, checking facts, generating user interest and feelings of involvement, identifying requirements, and gathering ideas and opinions. Observation is one of the most effective fact-finding techniques you can use to understand a system. With this technique, you can either par ¬ticipate in, or watch a person perform activities to learn about the system. This technique is particularly useful when the validity of data collected through other methods is in question or when the complexity of certain aspects of the system prevents a clear explanation by the end-users.A useful fact-finding technique is to research the application and prob ¬lem. Computer trade journals, reference books, and the Internet are good sources of information. They can provide you with information on how others have solved similar prob ¬lems, plus you can learn whether or not software packages exist to solve your problem. Another fact-finding technique is to conduct surveys through questionnaires. Questionnaires are special-purpose documents that allow you to gather facts from a large number of people while maintaining some control over their responses.When dealing with a large audience, no other fact-finding technique can tabulate the same facts as efficiently. 6. 5Describe the purpose of defining a mission statement and mission objectives for a database system. The mission statement defines the major aims of the database system. Those driving the database project within the business (such as the Director and/or owner) normally define the mission statement. A mission statement helps to clarify the purpose of the database project and provides a clearer path towards the efficient and effective creation of the required database system.Once the mission statement is defined, the next activity involves identifying the mission objectives. Each mission objective should identify a particular task that the database must support. The assumption is that if the database supports the mission objectives then the mission statement should be met. The mission statement and objectives may be accompanied with additional information that specifies, in general terms, the work to be done, the resources with which to do it, and the money to pay f or it all. 6. 6What is the purpose of the systems definition stage?The purpose of the system definition stage is to identify the scope and boundary of the database system and its major user views. Defining the scope and boundary of the database system helps to identify the main types of data mentioned in the interviews and a rough guide as to how this data is related. A user view represents the requirements that should be supported by a database system as defined by a particular job role (such as Manager or Assistant) or business application area (such as video rentals or stock control). 6. How do the contents of a users’ requirements specification differ from a systems specification? There are two main documents created during the requirements collection and analysis stage, namely the users’ requirements specification and the systems specification. The users’ requirements specification describes in detail the data to be held in the database and how the data is to be used. The systems specification describes any features to be included in the database system such as the required performance and the levels of security. 6. Describe one approach to deciding whether to use centralized, view integration, or a combination of both when developing a database system for multiple user views. One way to help you make a decision whether to use the centralized, view integration, or a combination of both approaches to manage multiple user views is to examine the overlap in terms of the data used between the user views identified during the system definition stage. It’s difficult to give precise rules as to when it’s appropriate to use the centralized or view integration approaches.As the database developer, you should base your decision on an assessment of the complexity of the database system and the degree of overlap between the various user views. However, whether you use the centralized or view integration approach or a mixture of both to build the underlying database, ultimately you need to create the original user views for the working database system. Chapter 7 Entity-Relationship Modeling – Review questions 7. 1Describe what entities represent in an ER model and provide examples of entities with a physical or conceptual existence.Entity is a set of objects with the same properties, which are identified by a user or company as having an independent existence. Each object, which should be uniquely identifiable within the set, is called an entity occurrence. An entity has an independent existence and can represent objects with a physical (or ‘real’) existence or objects with a conceptual (or ‘abstract’) existence. 7. 2Describe what relationships represent in an ER model and provide examples of unary, binary, and ternary relationships.Relationship is a set of meaningful associations among entities. As with entities, each association should be uniquely identifiable within the set. A uniquely identifiable association is called a relationship occurrence. Each relationship is given a name that describes its function. For example, the Actor entity is associated with the Role entity through a relationship called Plays, and the Role entity is associated with the Video entity through a relationship called Features. The entities involved in a particular relationship are referred to as participants.The number of participants in a relationship is called the degree and indicates the number of entities involved in a relationship. A relationship of degree one is called unary, which is commonly referred to as a recursive relationship. A unary relationship describes a relationship where the same entity participates more than once in different roles. An example of a unary relationship is Supervises, which represents an association of staff with a supervisor where the supervisor is also a member of staff.In other words, the Staff entity participates twice in the Supervises re lationship; the first participation as a supervisor, and the second participation as a member of staff who is supervised (supervisee). See Figure 7. 5 for a diagrammatic representation of the Supervises relationship. A relationship of degree two is called binary. A relationship of a degree higher than binary is called a complex relationship. A relationship of degree three is called ternary. An example of a ternary relationship is Registers with three participating entities, namely Branch, Staff, and Member.The purpose of this relationship is to represent the situation where a member of staff registers a member at a particular branch, allowing for members to register at more than one branch, and members of staff to move between branches. Figure 7. 4 Example of a ternary relationship called Registers. 7. 3Describe what attributes represent in an ER model and provide examples of simple, composite, single-value, multi-value, and derived attributes. An attribute is a property of an entit y or a relationship. Attributes represent what we want to know about entities.For example, a Video entity may be described by the catalogNo, title, category, dailyRental, and price attributes. These attributes hold values that describe each video occurrence, and represent the main source of data stored in the database. Simple attribute is an attribute composed of a single component. Simple attributes cannot be further subdivided. Examples of simple attributes include the category and price attributes for a video. Composite attribute is an attribute composed of multiple components. Composite attributes can be further divided to yield smaller components with an independent existence.For example, the name attribute of the Member entity with the value ‘Don Nelson’ can be subdivided into fName (‘Don’) and lName (‘Nelson’). Single-valued attribute is an attribute that holds a single value for an entity occurrence. The majority of attributes are singl e-valued for a particular entity. For example, each occurrence of the Video entity has a single-value for the catalogNo attribute (for example, 207132), and therefore the catalogNo attribute is referred to as being single-valued. Multi-valued attribute is an attribute that holds multiple values for an entity occurrence.Some attributes have multiple values for a particular entity. For example, each occurrence of the Video entity may have multiple values for the category attribute (for example, ‘Children’ and ‘Comedy’), and therefore the category attribute in this case would be multi-valued. A multi-valued attribute may have a set of values with specified lower and upper limits. For example, the category attribute may have between one and three values. Derived attribute is an attribute that represents a value that is derivable from the value of a related attribute, or set of attributes, not necessarily in the same entity.Some attributes may be related for a p articular entity. For example, the age of a member of staff (age) is derivable from the date of birth (DOB) attribute, and therefore the age and DOB attributes are related. We refer to the age attribute as a derived attribute, the value of which is derived from the DOB attribute. 7. 4Describe what multiplicity represents for a relationship. Multiplicity is the number of occurrences of one entity that may relate to a single occurrence of an associated entity. 7. 5What are business rules and how does multiplicity model these constraints?Multiplicity constrains the number of entity occurrences that relate to other entity occurrences through a particular relationship. Multiplicity is a representation of the policies established by the user or company, and is referred to as a business rule. Ensuring that all appropriate business rules are identified and represented is an important part of modeling a company. The multiplicity for a binary relationship is generally referred to as one-to-on e (1:1), one-to-many (1:*), or many-to-many (*:*). Examples of three types of relationships include: †¢A member of staff manages a branch. A branch has members of staff. †¢Actors play in videos. 7. 6How does multiplicity represent both the cardinality and the participation constraints on a relationship? Multiplicity actually consists of two separate constraints known as cardinality and participation. Cardinality describes the number of possible relationships for each participating entity. Participation determines whether all or only some entity occurrences participate in a relationship. The cardinality of a binary relationship is what we have been referring to as one-to-one, one-to-many, and many-to-many.A participation constraint represents whether all entity occurrences are involved in a particular relationship (mandatory participation) or only some (optional participation). The cardinality and participation constraints for the Staff Manages Branch relationship are shown in Figure 7. 11. 7. 7Provide an example of a relationship with attributes. An example of a relationship with an attribute is the relationship called PlaysIn, which associates the Actor and Video entities. We may wish to record the character played by an actor in a given video.This information is associated with the PlaysIn relationship rather than the Actor or Video entities. We create an attribute called character to store this information and assign it to the PlaysIn relationship, as illustrated in Figure 7. 12. Note, in this figure the character attribute is shown using the symbol for an entity; however, to distinguish between a relationship with an attribute and an entity, the rectangle representing the attribute is associated with the relationship using a dashed line. Figure 7. 12 A relationship called PlaysIn with an attribute called character. . 8Describe how strong and weak entities differ and provide an example of each. We can classify entities as being either strong or we ak. A strong entity is not dependent on the existence of another entity for its primary key. A weak entity is partially or wholly dependent on the existence of another entity, or entities, for its primary key. For example, as we can distinguish one actor from all other actors and one video from all other videos without the existence of any other entity, Actor and Video are referred to as being strong entities.In other words, the Actor and Video entities are strong because they have their own primary keys. An example of a weak entity called Role, which represents characters played by actors in videos. If we are unable to uniquely identify one Role entity occurrence from another without the existence of the Actor and Video entities, then Role is referred to as being a weak entity. In other words, the Role entity is weak because it has no primary key of its own. Figure 7. 6 Diagrammatic representation of attributes for the Video, Role, and Actor entities.Strong entities are sometimes r eferred to as parent, owner, or dominant entities and weak entities as child, dependent, or subordinate entities. 7. 9Describe how fan and chasm traps can occur in an ER model and how they can be resolved. Fan and chasm traps are two types of connection traps that can occur in ER models. The traps normally occur due to a misinterpretation of the meaning of certain relationships. In general, to identify connection traps we must ensure that the meaning of a relationship (and the business rule that it represents) is fully understood and clearly defined.If we don’t understand the relationships we may create a model that is not a true representation of the ‘real world’. A fan trap may occur when two entities have a 1:* relationship that fan out from a third entity, but the two entities should have a direct relationship between them to provide the necessary information. A fan trap may be resolved through the addition of a direct relationship between the two entities th at were originally separated by the third entity. A chasm trap may occur when an ER model suggests the existence of a relationship between entities, but the pathway does not exist between certain entity occurrences.More specifically, a chasm trap may occur where there is a relationship with optional participation that forms part of the pathway between the entities that are related. Again, a chasm trap may be resolved by the addition of a direct relationship between the two entities that were originally related through a pathway that included optional participation. Chapter 8 Normalization – Review questions 8. 1Discuss how normalization may be used in database design. Normalization can be used in database design in two ways: the first is to use ormalization as a bottom-up approach to database design; the second is to use normalization in conjunction with ER modeling. Using normalization as a bottom-up approach involves analyzing the associations between attributes and, based on this analysis, grouping the attributes together to form tables that represent entities and relationships. However, this approach becomes difficult with a large number of attributes, where it’s difficult to establish all the important associations between the attributes. Alternatively, you can use a top-down approach to database design.In this approach, we use ER modeling to create a data model that represents the main entities and relationships. We then translate the ER model into a set of tables that represents this data. It’s at this point that we use normalization to check whether the tables are well designed. 8. 2Describe the types of update anomalies that may occur on a table that has redundant data. Tables that have redundant data may have problems called update anomalies, which are classified as insertion, deletion, or modification anomalies. See Figure 8. 2 for an example of a table with redundant data called StaffBranch.There are two main types of insertion anomalies, which we illustrate using this table. Insertion anomalies (1)To insert the details of a new member of staff located at a given branch into the StaffBranch table, we must also enter the correct details for that branch. For example, to insert the details of a new member of staff at branch B002, we must enter the correct details of branch B002 so that the branch details are consistent with values for branch B002 in other records of the StaffBranch table. The data shown in the StaffBranch table is also shown in the Staff and Branch tables shown in Figure 8. 1.These tables do have redundant data and do not suffer from this potential inconsistency, because for each staff member we only enter the appropriate branch number into the Staff table. In addition, the details of branch B002 are recorded only once in the database as a single record in the Branch table. (2)To insert details of a new branch that currently has no members of staff into the StaffBranch table, it’s nec essary to enter nulls into the staff-related columns, such as staffNo. However, as staffNo is the primary key for the StaffBranch table, attempting to enter nulls for staffNo violates entity integrity, and is not allowed.The design of the tables shown in Figure 8. 1 avoids this problem because new branch details are entered into the Branch table separately from the staff details. The details of staff ultimately located at a new branch can be entered into the Staff table at a later date. Deletion anomalies If we delete a record from the StaffBranch table that represents the last member of staff located at a branch, the details about that branch are also lost from the database. For example, if we delete the record for staff Art Peters (S0415) from the StaffBranch table, the details relating to branch B003 are lost from the database.The design of the tables in Figure 8. 1 avoids this problem because branch records are stored separately from staff records and only the column branchNo re lates the two tables. If we delete the record for staff Art Peters (S0415) from the Staff table, the details on branch B003 in the Branch table remain unaffected. Modification anomalies If we want to change the value of one of the columns of a particular branch in the StaffBranch table, for example the telephone number for branch B001, we must update the records of all staff located at that branch.If this modification is not carried out on all the appropriate records of the StaffBranch table, the database will become inconsistent. In this example, branch B001 would have different telephone numbers in different staff records. The above examples illustrate that the Staff and Branch tables of Figure 8. 1 have more desirable properties than the StaffBranch table of Figure 8. 2. In the following sections, we examine how normal forms can be used to formalize the identification of tables that have desirable properties from those that may potentially suffer from update anomalies. . 3Describ e the characteristics of a table that violates first normal form (1NF) and then describe how such a table is converted to 1NF. The rule for first normal form (1NF) is a table in which the intersection of every column and record contains only one value. In other words a table that contains more than one atomic value in the intersection of one or more column for one or more records is not in 1NF. The non 1NF table can be converted to 1NF by restructuring original table by removing the column with the multi-values along with a copy of the primary key to create a new table.See Figure 8. 4 for an example of this approach. The advantage of this approach is that the resultant tables may be in normal forms later that 1NF. 8. 4What is the minimal normal form that a relation must satisfy? Provide a definition for this normal form. Only first normal form (1NF) is critical in creating appropriate tables for relational databases. All the subsequent normal forms are optional. However, to avoid th e update anomalies discussed in Section 8. 2, it’s normally recommended that you proceed to third normal form (3NF).First normal form (1NF) is a table in which the intersection of every column and record contains only one value. 8. 5Describe an approach to converting a first normal form (1NF) table to second normal form (2NF) table(s). Second normal form applies only to tables with composite primary keys, that is, tables with a primary key composed of two or more columns. A 1NF table with a single column primary key is automatically in at least 2NF. A second normal form (2NF) is a table that is already in 1NF and in which the values in each non-primary-key column can be worked out from the values in all the columns that makes up the primary key.A table in 1NF can be converted into 2NF by removing the columns that can be worked out from only part of the primary key. These columns are placed in a new table along with a copy of the part of the primary key that they can be worked out from. 8. 6Describe the characteristics of a table in second normal form (2NF). Second normal form (2NF) is a table that is already in 1NF and in which the values in each non-primary-key column can only be worked out from the values in all the columns that make up the primary key. 8. Describe what is meant by full functional dependency and describe how this type of dependency relates to 2NF. Provide an example to illustrate your answer. The formal definition of second normal form (2NF) is a table that is in first normal form and every non-primary-key column is fully functionally dependent on the primary key. Full functional dependency indicates that if A and B are columns of a table, B is fully functionally dependent on A, if B is not dependent on any subset of A. If B is dependent on a subset of A, this is referred to as a partial dependency.If a partial dependency exists on the primary key, the table is not in 2NF. The partial dependency must be removed for a table to achieve 2NF. See Section 8. 4 for an example. 8. 8Describe the characteristics of a table in third normal form (3NF). Third normal form (3NF) is a table that is already in 1NF and 2NF, and in which the values in all non-primary-key columns can be worked out from only the primary key (or candidate key) column(s) and no other columns. 8. 9Describe what is meant by transitive dependency and describe how this type of dependency relates to 3NF. Provide an example to illustrate your answer.The formal definition for third normal form (3NF) is a table that is in first and second normal forms and in which no non-primary-key column is transitively dependent on the primary key. Transitive dependency is a type of functional dependency that occurs when a particular type of relationship holds between columns of a table. For example, consider a table with columns A, B, and C. If B is functionally dependent on A (A ? B) and C is functionally dependent on B (B ? C), then C is transitively dependent on A via B (provided that A is not functionally dependent on B or C).If a transitive dependency exists on the primary key, the table is not in 3NF. The transitive dependency must be removed for a table to achieve 3NF. See Section 8. 5 for an example. Chapter 9 Logical Database Design – Step 1- Review questions 9. 1Describe the purpose of a design methodology. A design methodology is a structured approach that uses procedures, techniques, tools, and documentation aids to support and facilitate the process of design. 9. 2Describe the main phases involved in database design. Database design is made up of two main phases: logical and physical database design.Logical database design is the process of constructing a model of the data used in a company based on a specific data model, but independent of a particular DBMS and other physical considerations. In the logical database design phase we build the logical representation of the database, which includes identification of the important e ntities and relationships, and then translate this representation to a set of tables. The logical data model is a source of information for the physical design phase, providing the physical database designer with a vehicle for making tradeoffs that are very important to the design of an efficient database.Physical database design is the process of producing a description of the implementation of the database on secondary storage; it describes the base tables, file organizations, and indexes used to achieve efficient access to the data, and any associated integrity constraints and security restrictions. In the physical database design phase we decide how the logical design is to be physically implemented in the target relational DBMS. This phase allows the designer to make decisions on how the database is to be implemented. Therefore, physical design is tailored to a specific DBMS. . 3Identify important factors in the success of database design. The following are important factors to the success of database design: †¢Work interactively with the users as much as possible. †¢Follow a structured methodology throughout the data modeling process. †¢Employ a data-driven approach. †¢Incorporate structural and integrity considerations into the data models. †¢Use normalization and transaction validation techniques in the methodology. †¢Use diagrams to represent as much of the data models as possible. †¢Use a database design language (DBDL). Build a data dictionary to supplement the data model diagrams. †¢Be willing to repeat steps. 9. 4Discuss the important role played by users in the process of database design. Users play an essential role in confirming that the logical database design is meeting their requirements. Logical database design is made up of two steps and at the end of each step (Steps 1. 9 and 2. 5) users are required to review the design and provide feedback to the designer. Once the logical database design has been ‘signed off’ by the users the designer can continue to the physical d

Animal Abuse Essay

The Greyhound is an ancient breed of dog. It is the only dog mentioned in the Bible, and has been depicted in many ancient Egyptian paintings, dating back over 4,000 years. Greyhounds were so revered, that the Greyhounds were allowed to share their tents. In ancient Arabic countries, the birth of a son was the most important event, the second was the birth of a Greyhound. The history of dog racing can be traced back to Queen Elizabeth I in the 16th century when Greyhounds were brought over to England from Egypt, where her majesty created the first formal rules of dog coursing, naming it the â€Å"Sport of Queens†. In the 18th century, England exported the sport to America, and soon the sport was comprised of racing and gambling. In 1912, the dog racing as it is known today, was established by Owen Patrick Smith, the man who invented the mechanical lure used in today’s dog racing. The first official dog track was opened in 1919 in California, and in 1931, wagering was legalized in Florida, paving the way for the development of the Palm Beach Kennel Club. The Palm Beach Kennel Club operated permits for dog racing, which officially started in America in 1932. Unfortunately, the once grandeur and majesty of the sport is tarnished with the unethical abuse these animals endure. The definition of animal abuse is â€Å"the crime of inflicting physical pain, suffering or death on an animal, usually a tame one, beyond necessity for normal discipline. It can include neglect that is so monstrous (withholding food and water) that the animal has suffered, died or been put in imminent danger of death. † (Hill, 2005). Many Greyhounds are the subject of abuse in the racing world. The Greyhounds are subject to horrible conditions. Many people enjoy watching a good race. The anticipation of the race and the thrill of their prized dog winning would make anyone want to attend a race. But it’s what happens before and after the race that has many people up in arms over the whole dog racing scene. When the dogs are not racing, they are kept in crates stacked one on top of the other. The dogs are not exercised regularly; the only exercise they get is from racing, and a race lasts for only a few minutes. If an Greyhound is injured during practice or during the race, the dog is killed and ground up for food for the other dogs. Many Greyhounds also die during the race due to exhaustion and dehydration. It is important to address this issue because animal abuse is a crime, and most people who commit these heinous acts are never brought to justice. It is also important to understand why someone could harm an innocent animal. According to the ASPCA, there are three main reasons why someone would be cruel to animals in their article titled, Why people abuse animals. The first reason is that some people abuse animals is that they do not know they are abusing the animal. Some people just don’t think about what they are doing to the animal, and others think excessive force is necessary to maintain control of the animal. A person who hits their dog when he or she does something wrong, like poop in the house, will use excessive force to show the animal that what he or she did was bad. Other people forget to roll down a window on a hot day with the animal in the car. The second reason a person would abuse animals is that the person will do it purposefully, but not for a continuous amount of time. Young kids who throw rocks at cats or kick a dog are an example of this type of abuser. Many young children can be taught through support groups and educational programs to show how an animal feels when it is abused in such a way, and many children learn to respect animals. The third reason a person would abuse an animal is the most serious form of animal cruelty. The third reason a person would abuse an animal is for power. Many of these types of people enjoy hurting the weak and helpless animals, as it makes them feel in control. Most of these people who intentionally hurt an animal have serious psychological issues that need to be addressed. If left unchecked, these issues may lead to more serious acts of violence. According the article, most people that were mentioned in the first and second reason for animal abuse can be educated through materials, counselors and educational classes. But even with the educational classes, what most people don’t understand is the psychological effects of the abuse has on animals. All animals want is to be loved and cared for, especially dogs. Humans have breed dogs to be our companions, and are the only animal that sets out to please us. When a human abuses an animal, we lose that trust that the animal places in us. The main psychological effect abuse has on dogs can be devastating. A dog may feel threatened by any human that it comes in contact with, and the dog can turn aggressive out of fear. Other dogs are fearful and maintain their fearfulness throughout the rest of their lives. These dogs may cower away from humans, shunning away when a human has an object in their hand or hide when they hear raised voices. L. Kalef wrote an article titled Psychological effects of animal cruelty, and in the article, he talked about the effects of animal abuse in Eastern Europe. For those who have traveled to Eastern European countries, it is not uncommon to be privy to packs of dogs roaming in some of the major cities, and sometimes being aggressive out of fear, hunger or abuse have led to provoke a similar reaction by the population by way of harm and abuse. Sadly, these neglected animals are under constant scrutiny and possible attack, which has become all too common. For years, welfare activists have been speaking up for the plight of the strays and the brutal inhumane abuse and killings; but no one until now has suggested that the constant exposure of this violence may instigate other and further violent activity within the community. In other words, growing up in a society being exposed to animal abuse causes further abuse and lack of compassion. (Kalef, 2012) But there are many people who argue that dog racing is not the only animal sport that has animal abuse and that it is part of the sport. Throughout the world of animal sports, there are some instances of animal abuse. In Mexico, bullfighting is a very popular sport, where the object of the game is to kill the bull or else the Matador will be stampeded or stabbed by the bulls horns. The bulls are starved and tortured, and they meaner the bull becomes, the more entertaining the sport. Also, horse racing has had its fair share of animal abuse cases. Many Thoroughbreds that receive an injury are killed, just like the Greyhounds, and made into meat that is sold for human consumption. J. Frater wrote an article titled 10 Debated acts of animal cruelty, which outlines a few instances that can be considered animal abuse. For those who have traveled to Eastern European countries, it is not uncommon to be privy to packs of dogs roaming in some of the major cities, and sometimes being aggressive out of fear, hunger or abuse have led to provoke a similar reaction by the population by way of harm and abuse. Sadly, these neglected animals are under constant scrutiny and possible attack, which has become all too common. For years, welfare activists have been speaking up for the plight of the strays and the brutal inhumane abuse and killings; but no one until now has suggested that the constant exposure of this violence may instigate other and further violent activity within the community. In other words, growing up in a society being exposed to animal abuse causes further abuse and lack of compassion. (Frater, 2010). But to most people, that is just the way the sport is. What is someone going to do with a prized race horse that has a broken leg and can no longer race? Why take the money to fix the injury, when the owner can make money off of selling the animal for food? It’s just part of the sport. But there is one question that needs to be answered. Which side is right? The truth is both sides are right. There will always be animal abuse in sports, as well as throughout the world. We as a people will not be able to completely stop the abuse, we can just diminish the amount of animals are abused. Through the use of stricter laws and more regulations, we as humans can help the voiceless. In conclusion, though there is no one way to solve animal cruelty in the world. There will always be animal cruelty in the sporting world, but as long as we humans can educate the younger generations, the amount of cases of animal cruelty will drastically decrease. Only one can hope that the â€Å"Sport of Queens† can return once again to the grandeur and majesty that the sport once was.

Amicus Brief (Abortion) Essay Example | Topics and Well Written Essays - 4000 words

Amicus Brief (Abortion) - Essay Example his brief before the Court as an amicus curiae for the purpose of pointing out to the Court the errors of law committed by the Supreme Court of Freedonia when it upheld the state of Freedonia over the herein petitioner Jane Roe in regard to the constitutionality of the Freedonia Abortion Act 2009. The UK and the United States are both State Parties to the International Covenant on Civil and Political Rights (ICCPR hereafter). On December 16, 1966 in New York, the ICCPR, a United Nations initiated covenant, was declared open for signature. The UK signed it on September 16, 1968 with its ratification papers duly submitted to the Committee on May 20, 1976. As per the Committee records, the US signed the covenant on October 5, 1977 and ratified it on June 8, 1992 (UN Treaty Collection). Under international laws, the US is obliged to comply with the provisions of international treaties, like the ICCPR to which it is a state party. In upholding international treaties, like the ICCPR, respecting civil rights of citizens, the UK has passed into law the Abortion Act of 1967 and other related laws like the Human Fertilisation Act 1990 (amended in 2000). Unlike the US federal system in which fifty-states are free to enact their respective abortion-related laws so long as they do not contravene the US Constitution, the UK, a unitary state, has one set of abortion laws applicable all throughout its jurisdiction, except for Northern Ireland in respect to abortion laws. In UK, except for Northern Ireland, abortion is legal. A woman can opt for abortion up to the 24th week of conception if two doctors can attest that she or her children, runs a risk, physically and mentally, if the pregnancy is carried to its full term. The limit, however, is not applicable if two doctors agree that a woman’s pregnancy places her life at risk if she continues with the pregnancy or the child is likely to be born with serious physical or mental defects or to save the woman’s life or to

The Theme Of Happiness In The Movie Revolutionary Road Essay

The Theme Of Happiness In The Movie Revolutionary Road - Essay Example I feel the frustrations of not achieving their dreams could have polarized the relationship. Finding purpose and meaning in life has lasting impact one's well-being. Occasionally, this results from having fulfilled dreams. Living below your dreams can lead to mental distress and become unable to cope with life issues. The quick turn of events changes the platform to achieve the dreams for the two lovers. Frank gets promotion and April are pregnant again. The frustrations grew up to the point of break up. True to Friedan, a magazine analyst, words, women in The New Woman Heroine yearn for career growth, self-identity and if they did not make it, those dreams would still be burning inside them to a point that they would wish their daughters to live their dreams. Looking at April, I can understand why she had to do what she did. She did not have anything to hold on in life. Her career becoming close to impossible to achieve and unhappy marriage running in her hand every time she would think of it was enough to torture her to death. Everyone wants to achieve the life’s dream and if not have something that closely resembles such dreams. It gives purpose and meaning which I believe lacked for the couple. I feel like no one can understand our dreams better than we do and hence the need to follow our  heart.

How has UK joining the European Union impacted the doctrine of Essay - 1

How has UK joining the European Union impacted the doctrine of parliamentary sovereignty - Essay Example essure because of some statutory reforms passed by former regimes affiliated to the Labour party in early 1970s and consequently at the end of the 20th century. Tracking back to the 70s era, the British government enacted laws that saw it join the European Communities (Gifford 2009). Their entry into the European Union brought about some fundamental effects in the UKs parliamentary sovereignty. The principle of UKs Parliamentary sovereignty is derived from historical events that took place in late 1600s. Scholar’s trackback parliamentary sovereignty to the Glorious Revolution that took place in the year 1688. It is regarded by certain individuals as being a significant occasion in the lengthy growth of the separate powers and privileges of the UK Parliament, creating the dominance of laws over prerequisite powers. The UKs Parliament statutory power comprises not only the ability to amend the laws, but also the fact that no other institution within the constitution should have the power of doing so, other than the parliament. By Parliaments sovereignty, it is predestined that there are no statutory restrictions on jurisdictive powers and influences of the UK parliament (McGarry 2012). The Queen gives the bills that are approved by both houses namely: - the House of Commons and the House of Lords the Royal Assent to transform them to become Acts of "the UK" Parliament . Parliamentary Sovereignty additionally includes the notion that the UK courts are compelled to empower laws that are ratified by the UK parliament and to not question the decisions of the parliament exemplified in the statute. According to Albert Venn Dicey, the parliament has a right to unmake or make any rule and there is no other individual or institution recognized under the UK law, who has the mandate to supersede or set aside parliaments legislation. This declaration by Dicey demonstrates the typical explanation of the principle of Parliamentary dominance. It is, however, said that this

Micro and Macro Economics Analysis of British Airways Coursework

Micro and Macro Economics Analysis of British Airways - Coursework Example Microeconomic Analysis Some of the demand and supply factors that have affected the profitability of British Airways as a company over the years include economic conditions, competition from other airlines, rise and fall in global oil prices, changes in government policy, and employees’ expenses. Economic conditions include one important demand and supply factor that affects the profitability of British Airways. For example, in the first few years of the new millennium, global recession has hit hard the company’s profitability. Generally, global recession means that the world’s economy is shrinking. A bad economy means that many people will not have a lot of money in their accounts to tour the world and in the process, affecting the company’s demand. This in the long run affects the profits of the company. Competition from other airlines is also a factor that affects the British Airways’ profitability. In the new millennium, the emergence of many lo w-cost airlines has really affected the company’s profitability by reducing the demand. ... When global oil prices rise, the cost of jet fuel, which is a by-product of the refined oil, will also rise. This will lead to a significant rise in the price of air tickets and in the long run, reducing the demand as well as the company’s profits tremendously. The vice-versa happens when the global oil prices fall. Recently, when oil prices rose, knowing that this would affect the company’s profits tremendously, BA executives took part in an illegal act of fixing fuel surcharges. This led to the fining of BA and the executives charged with a criminal act (Thompson and Martin, 2010, p.298) Government policy also affects the company’s profitability. When the government issues travel advisories to some destinations in the world due to terrorist attacks, the number of travelers to those destinations goes down and in the process reduces the company’s profits that would have been made in travels to those destinations. For example, the terrorist attacks on the W orld trade center had the government informing people of how the situation on the ground was and in the process, the number of travelers reduced tremendously bringing down the company’s profits. Employees’ expense is another factor that affects British Airways profitability. It forms a big part of the company’s costs which are later passed down to the travelers and which affects demand. For example, in 2002 when the British Airways was restructuring its business operations, it had to have 13,000 job cuts. This job cuts were an attempt by the company to cut its costs by 650 million pounds. This showed how employee expenses as a factor has a big impact on the company’s profitability (Young, 2007, p.42) Â   Â   The market structure in which the chosen company operates in is a

Maximum height of a projectile motion Lab Report

Maximum height of a projectile motion - Lab Report Example Since the gravitational pull acts downwards (vertical sense) then the horizontal and vertical components can be treated separately. Thus, the maximum height traveled by the body upwards can be calculated (Warren 73). For instance, a cannon shoots a ten kilograms cannon balls straight upwards, with a muzzle velocity of say 860 m/s, and then ignoring air resistance the maximum height attained by the cannon balls can be found. Taking the initial velocity in the vertical direction of the cannon ball to be vi and bearing in mind that the acceleration due to gravity is acting in the opposite direction (downwards). At the point when the cannonball attains the maximum height, it has zero velocity thus vf = 0. At this point, the ball starts to accelerate downwards. The equation below is used to calculate the cannon’s highest point that it reaches before it starts falling downwards (Warren 72). Thus, the ball will go up to thirty-eight kilometers or approximately twenty-four miles (Serway, Jewett and Peroomian 20). Theoretically, the ball should come back and attain the velocity same as the launching velocity as it falls at the same point of launching, that is 860 m/s. At each angle of elevation, the initial velocities were noted (McGinnis 73). The same procedure was repeated for the ball with a mass of 5.50 grams. The results were tabulated in a table as shown below: The result of the heights corresponding to every velocity was obtained, and curves were drawn for every mass. The results were as shown below. The table shows the results obtained for the ball of mass 9.5 g. The data obtained for the two balls was tabulated, and the maximum height reached by the ball at each launch relative to the angle of elevation was found (Breithaupt 26). The maximum height was determined using the formulae in the equation (7). H max = †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. (7). Each ball was launched at its time, and the muzzle velocities were maintained

Research Methods in Social Work Paper Example | Topics and Well Written Essays - 250 words

Methods in Social Work - Research Paper Example This means that the better part of the active population of the society was captured. The sample size randomly selected from the different age groupings was 300 students. These students were taken through an oral interview on the amount of time that should be put on entertainment and this was the findings; 17yrs to 29yrs preferred 5 days a week, 30yrs to 38yrs opted for 3 days a week and the upper end of the age group proposed twice a week. This was a representative sample to the population at more than 30% and the findings give a true reflection of the general behavior across the social life of different age brackets in the world (Proquest, 2012). A survey undertaken by Gallup in December 2008 with a sample of 1500 people established that 44% of the Pakistani feels that Taliban has a negative influence In the social, economic and political aspect of their nation (Gallup world, 2009). This was not a sufficient representative sample to the population of about 177 (World Bank, 2011) million people but aspiring political leaders to formulate winning strategies could still use this. The political survey needs to capture regional dispersions and social stratification. A survey was conducted by the Princeton Survey Research Associates for The Pew Research Center for the People & the Press asking the question ‘Women get fewer opportunities than men for good jobs (Pew Research Center, 2012)? The survey only interviewed 3008 people from a total American population of 311,591,917 (U.S. Census Bureau, 2011) to publish the results and deem them accurate. This survey can be used by NGOs and different organizations championing women rights to further their propaganda against employers.

Comorbidity Eating Disorders and Substance Abuse Essay

Comorbidity Eating Disorders and Substance Abuse - Essay Example Using a behavior specific approach in a community-based sample, Piran and Robinson (2005) found that as disordered eating behaviors became more severe, or were clustered together, the number of substance classes used increased. In addition, particular eating disordered behaviors were differentially related to the use of various substance classes. The study of the comorbidity between disordered eating and substance use in middle and high schools samples tended to focus on the association between attitudes toward eating, weight, and shape and tobacco smoking, alcohol drinking, and marijuana use (Field et al., 2002). Nonetheless, several school-based studies have also reported on associations between tobacco smoking, alcohol drinking, and marijuana use in relation to bingeing, purging and dieting behaviors (Lock et al., 2001 and Tomori et al., 2001). However, only a few investigations have included a broader range of substance classes while investigating associations between disordered eating attitudes and behaviors and substance use in school-based studies (Von Ranson et al., 2002). Tomori et al. ... (2002) found an association between the revised EDI subscales of Binge Eating, Body Dissatisfaction, and Compensating Behaviors, and the use of a wide range of illicit drugs. There are a small number of studies that have examined the relationship between problematic eating patterns and substance use in university samples (Anderson et al., 2005, Dunn et al., 2002, Krahn et al., 2005, Saules et al., 2004,). Several of these studies have focused on the relationship between bulimic symptomatology and substance use (Dunn et al., 2002 and Krahn et al., 2005). For example, Dunn et al. (2002) found no difference in patterns of alcohol use among college-age non-treatment seeking females with and without bulimia nervosa. The investigators did, however, find differences between the groups in their reported use of marijuana, opiates, and barbiturates. Krahn et al. (2005) found that the quantity and frequency of alcohol consumption were positively associated with a measure that assessed the combined severity of engagement in bingeing, dieting, and purging behaviors. In their study, smoking cigarettes, even at very low levels, was also related to the measure of combine d disordered eating behaviors. Other university-based studies have explored the relationship between disordered eating attitudes and behaviors as measured on the Eating Disorder Inventory (EDI) and substance abuse. Krahn et al. (2005) reported a positive significant, albeit small, association between problematic alcohol use in female undergraduate students and the EDI subscales of Bulimia and Interoceptive Awareness, but no such correlation with the other EDI subscales. No significant relationships were found between EDI subscales and use of other substances,

Conscious Performance Analysis or CPA Essay Example | Topics and Well Written Essays - 3000 words

Conscious Performance Analysis or CPA - Essay Example In fact, being a skeptic, I would say that there is plenty of evidence to support the notion that most people do not invest any time into going beyond the Wondering Operation that involves attending to what interests them and ignoring what is of no interest. Critical Operations follow for those who find CPA a useful exercise, but unfortunately, most people find interest only in superficiality of the bag of chips they are devouring while sitting on their couch in front of their big screen watching Dancing with the Stars. The popularity of such superficial and meaningless programming as well as the rising obesity rates proves this assertion, or at least makes a very strong argument in favor of the assertion. The real value in CPA comes from the fact that it can lead people out of that inattentive, lazy place into a more enlightened, more examined life that truly is worth living. Americans especially, but I am sure that it occurs in other countries too, are lazy. The effort required to perform CPA and to do so on a regular basis is much more than most people have in them. So, those who do actively seek meaning, objectivity, knowledge, truth, reality, and value, even if they do not realize that they are performing CPA, are few and far between. To me to assume that most people do want to find greater meaning in their lives seems optimistic. One would have to credit the general population with a lot more gumption than I am willing to credit them with, but only because I see the results of the general ennui of society. Nobody cares for each other and only in a genuine concern for each other can life actually have meaning. People only care about themselves and it is proven day in and day out. Take Black Friday for example. Shoppers stepped around and over a dying man and sprayed each other with pepper spray just to be first to get a cheap video game console so they can go home and resume being lazy in front of the television. These sorts of examples do not bode well fo r the future of humanity These pepper-spraying, bargain hunting people are only one kind of people, of course, and CPA does â€Å"distinguish types of subjects by the kinds of meaning they’re most interested in, the kinds of knowledge they most desire, the domains of reality they inhabit and in which they’re most comfortable, the kinds of values that concern them most† (87). Another kind of subject would be those at the other end of the spectrum, those who genuinely seek meaningful purpose in their lives through self-knowledge and self-possession. These people exhibit a basic commitment toward meaning, objectivity, knowledge, truth, reality, and value by wondering about the way they approach the events of their lives, and by critically analyzing not only the content and sequence of the events, but also their method of experiencing the events. Using CPA allows a person to experience life’s events more fully. After learning about CPA, I thought of some of t he past moments of my life and realized that some of them passed by and now I have few memories of them. For instance, I only vaguely remember my high school graduation. That is a pretty important day, but I just remember being nervous and not really wanting to walk across the stage in my clunky shoes to get my diploma. I thought for sure I was going to trip and fall. I do not remember being proud, just glad that I was finished with that portion of my life and ready to move on with the next. I do not remember any great feeling of achievement either. However, now looking back I see my high school graduation as a sign post in my life. When the principal of my school handed me that

A Horrid Memory Essay Example for Free

A Horrid Memory Essay My sweaty palms ran through-out the thin strands of my hair as I tried to comfort myself for just a single moment. I felt scared, almost terrified as the screams of my nightmare echoed in my ears and made my head throb. Almost never did I have such vivid dreams, and when I did, I never remembered them the next day. Nevertheless, I dont think that Ill ever be able to make amends with my darkest memories and reliving situations that scarred my childhood and eventually my life, can never be forgotten. All I can do is go back and ask what this version of myself could have done to avoid or even confront the situations and events. Around me, there were four chairs, each one with a primary colors: blue, red, green and yellow, around the circular, light wooden table, and of course, I was in one of them. In front of me, was my mother, who had a slim and petite figure, dark brown hair, as well as matching brown eyes and tanned skin; she was feeding the birthday girl, who was a 1 year toddler. Next to me was my six year old sister, and she had pale skin with orange colored freckles, almond shaped eyes and chestnut hair. On the right side of the table, was my stepfather, who was visibly, a few drinks from drunk, and you could notice it by the scent coming out of his mouth and his blood shot eyes. He was also pale, freckles everywhere and bold eyes that made little statement thanks to his glasses. I was about thirteen years old, and I can still recall the smell of a hot and cheesy plate of macaroni, and each bite that I took of it was better than the one before. But I was so focused in my delicious food, that I hadnt realized the silence that crept over the entire table. Feeling like there was an absence of a healthy family conversation, I tried to create a conversation â€Å"So.. What did you guys do today? † I said, feeling my eyes were full of excitement and content, food always had that effect on me. Four pairs of eyes were staring at me, and I began to drop my fork as I saw my stepfather placing a knife against his five-o-clock shadow. Everyone in the table stared at him, and I immediately started to feel uncomfortable. â€Å"Is it true what Isabel told me? † His voice was cold, dark and had a sense of hidden humor, it felt like a horror movie. Our eyes then shifted towards Isabel, my little sister, and she looked like she had just fallen into a hole and had no idea how to get out of it. â€Å"She told me that you guys didnt love me, you guys didnt want me. † He spoke once again with the same tone, and at first, I thought he was joking, so I laughed but then I was rewarded with a deadly glare, which let me know that he wasnt joking. The air around the room got thin, and I could feel the walls trying to suffocate me. My mom, knowing he was drunk, had an annoyed expression planted on her face. â€Å"No, we never said that, now finish up your plate. I think its time for you to go to bed. † She usually had pretty low tolerance with drunk people, and her husband was no exception. I think that the only one that wasnt in tension, was my 1 year old sister, Dianelle because she couldnt understand dialogue, what we were saying. He shoved the plate from the edge of the table, and soon after, I heard it smash against the ground. After being well aware about what was going to happen next, I took Dianelle into my arms and let my mother handle the situation before I said anything that would make him angrier. Nelson, my stepfather, got up from his chair and went to the kitchen cabinets to get something and when he turned around, he had a jalapeno mixed with DonQ spice in his hand. â€Å"You know what happens when you lie to me? You get jalapeno in your mouth. † He must have been mentally sick, because he was actually laughing. As a result of the emitted screams, yells and pleading for him to stop, the police came and took him away, right after he took out the butcher knife. In those three months that he wasnt around, it had probably been the most peaceful moments that my mother and my sisters spent together, we were even closer. The house was calm, the flowers smelled better and I didnt feel in danger or threatened while he was gone. But he eventually came back, and my mom accepted him, with the excuse of a face that he always made, opening his eyes widely and puckering his lips, trying to make a puppy dog face and he always got everyone to laugh. Ive learned that no matter how much you love someone, theyre never worth hurting the rest of the people around you, that love you.

The relationship between cannabis use and mental health disorder

The relationship between cannabis use and mental health disorder Abstract This assignment evaluates the relationship between cannabis use and mental health disorder related to it in Australia. Recent national data reflects that cannabis use was at its peak in 1998 when over 60% of people aged 20-29 were reported having used cannabis. Since then various studies have found co relation between cannabis use causing no mental health issues and cannabis use causing schizophrenia and psychosis. Recent studies have found that cannabis is recognized in Australia as the third most prevalent drug of dependence following alcohol and tobacco. About 10% of people who try cannabis will develop dependence at some point in their life. Studies have found relationship between weekly frequency of cannabis use and mental illness such particularly psychosis, schizophrenia, anxiety and depression (www.mhca.org.au). Introduction Cannabis is a plant contains a psychoactive molecule that produces a high associated with this drug. The psychoactive product contains dried flowers and leaves of plants selected to produce high levels of tetrahydrocannabinol (www.dictionary.com). There is a significant and growing research on the relationship between mental illness and cannabis use in Australia. The evidence supports the association between mental illness and regular cannabis use. The evidence states that regular cannabis use from young age will increases the risk of mental illness since there is genetic vulnerability to psychosis being which can be triggered by cannabis use. Evidence shows that cannabis use facilitates schizophrenia in people who have family history of mental illnesses. The average first use of cannabis users is now 14.9 years. This is of a very important concern in Australia as this is the age at which there are psychological changes in brain. Psychosis is an abnormal condition of the mind in gene ric psychiatric term for a mental state is often described as a loss of contact with the reality. This disorder can disable the normal functioning of the brain. This malfunction in brain causes people with elevated risk of death by suicide. Thus it is important to analyse the evidence carefully in order to make conclusions and recommendations (Hall et al, 2004). Relationship between Mental Illness and Cannabis. Certain pockets of Australian population consume cannabis in form of heating or ignition combined with inhalation of smoke or oral consumption of the plant itself mixed into a food medium. The other way that individuals consume cannabis is by vaporization, which causes the active ingredients to evaporate into gas without burning the plant material. This is generally done by boiling the ingredients of cannabis plant. Once these vapours are inhaled, it produces various short term and long term effects. The short term effects range from sleepiness, difficulty keeping track of time, impaired or reduced short term memory. In my general practice I have observed that the patients consuming high amount of cannabis find it hard to communicate and focus. They are generally slower to react and have increased heart rate, heart palpitations and show signs of psychological dependence on cannabis drug consumption. Their reasons for addiction generally range from recreational purposes and sometimes to escape their present hardships in life (Personal Communication, Clinical Placement, 2010). Evidence shown by scientific research shows that potential harm of cannabis use is generally and especially in vulnerable groups such as Aboriginal, young people, people belonging to poor socio economic background. The habit starts from peer pressure and gradually becomes an addiction. Rates of cannabis use by people with mental illness such as anxiety and depression also show heavy use of cannabis use.(Castle, 2004) The self medication hypothesis states that people experiencing signs of mental health disorder consume cannabis in order to alleviate or increase symptoms. There have been longitudinal studies to determine whether the mental illness is related to cannabis use. The hypothesis covers two scenarios -that cannabis initiates mental disorder that were previously lying inactive and that cannabis causes mental health illness who would not otherwise develop them. Thus research has been conducted on biological mechanisms such as effects of cannabis on brain chemistry and its effects on people without genetic predisposition to mental illness. Other social effects are taken into consideration when researching on cannabis users exposed to factors such as poor mental health, substance using peers, school dropout, unemployment and crime. It is a difficult to justify the effects of cannabis on an individual if many variables co exist both for the cannabis user and people with other social vulnerabil ities including family difficulties. Thus it is possible that there is a common genetic factor that predisposes individuals to cannabis use and mental illness (Patton et al, 2002). According to DSouza et al (2004) there is little dispute that cannabis can produce short term recurrences of pre existing psychotic symptoms. However there is no evidence relating to the fact that cannabis actually causes schizophrenia or other psychotic illness in long term (Johns, 2001). Research also shows that cannabis can also amplify a pre existing thought in an individual. These thoughts tend to overwhelm the individual causing severe reactions by individuals including suicide and self harm in extreme cases. In order for ascertain the research Hill (1965) states that following criteria must be met: Strength, consistency, specificity, temporality, biological gradient, coherence and plausibility. Every case needs to support each criteria to make the hypothesis stronger. Relationship between Cannabis consumption and Psychosis A recent study conducted by Hldes et al (2006) states that there is a two way relationship between psychosis and cannabis which states that regular use of cannabis is associated with higher risk of psychotic relapse. Many longitudinal studies have found that the mental illness particularly psychosis leads to increased use of cannabis. Research conducted by Hall et al (2004) states that most common symptoms related to the individuals with psychosis smoking cannabis were sudden confusion which were generally related to delusions and hallucinations. Their emotional state became unstable and showed signs of paranoid symptoms. These findings have been supported by individuals suggesting that they took large doses of cannabis product. Most of these people had no family history of psychosis. Their symptoms were gone once the individuals stopped their cannabis intake. These symptoms were seen back within days once the individuals started cannabis consumption again. Thus this evidence supports the hypothesis that the regular use of cannabis increases chances of psychosis in an individual. On the other hand the other hypothesis can be argued that cannabis intake does not support psychosis. There have been number of studies conducted that have compared people with people who have mental illness post cannabis use and who have developed mental illness prior to cannabis consumption. There is always a little variation in the results. According to Mental health council of Australia, there have been number of researches that have been conducted investigating the cannabis use among individuals with psychotic disorders and found that they were not significantly different from the general population. A range of motive can be grouped into following four categories: coping with unpleasant affect (to relieve emotional distress), enhancement (to have fun), social interaction (to affiliate with others), confirming (to fit in) (www.mhca.org.au) The evidence obtained shows that the first two tend to be heavy cannabis consumers and the later two are just recreational. The first two consume cannabis to relieve themselves from emotional distress, psychotic symptoms and medication side effects which lead them to consume heavy amounts of cannabis in order to feel that state of mind and emotion. People with psychosis initially use substance to change their emotional state and facilitate social contact. They then develop dependence on this substance stating, If I dont smoke then I will not be able to cope. These individuals then have belief that cannabis is the only way out thus worsening their psyche and this will lead to worsening cannabis dependence (Spence in Castle and Murray, 2004) Conclusion Various cases and individual analysis state that there is a strong connection between cannabis consumption and psychosis. The hypothesis states individuals consuming cannabis have developed symptoms of psychosis and these individuals have normalised once they stopped consuming cannabis. Thus, there is some evidence that suggest that cannabis consumption will impact the psyche of an individual but these findings are inconclusive at this stage as it fails to take into consideration other variables such as socioeconomic background, mental state, lack of family and community support. Relationship between Cannabis Consumption and Schizophrenia Schizophrenia is a mental illness caused by disintegration of thinking process and disorientated emotional response. It usually consists of hallucinations, paranoid, disorganized speech and thinking process with social and occupational dysfunction, withdrawal from reality, social apathy (www.dictionary.com) According to research by Mental Health Council of Australia relationship between Schizophrenia and cannabis use is growing though by no means comprehensive. Schizophrenia affects one percent of the Australian population. Smaller but substantial bodies of research exist such as depression and anxiety. In some cases, Schizophrenic patients had previous symptoms of psychotic illness (Hall et al, 2004). In research conducted on 100 young people consuming high amount of cannabis, 49% male with an average age of 19.3 years were identified at ultra high risk of psychosis. Schizophrenia was the symptom with presence of other acute psychotic symptoms. This research is very difficult due to the fact that there are many variables that co exist both cannabis users with mental health illness and non cannabis users with mental health difficulties have similar behavioural problem. Most of them have substance abuse history, unemployment and life time on benefits past. It can be possible that these are the common genetic factors in both cannabis users with mental health issues and non cannabis users with mental health issues (www.mhca.org.au). Longitudinal studies show that continuous cannabis consumption in people with schizophrenia is associated with worse mental health outcome in terms of more severe symptoms and thus there is a greater chance of relapse and more psychosocial issues. Thus frequent cannabis use is associated with a higher risk of psychotic relapse and a more increased risk of cannabis relapse (Hides et al, 2006). Studies conducted by Arsenault et al, (2004) cite cross national surveys from USA, Netherlands and USA found rates of cannabis consumption among people with Schizophrenia was double than those of general population. Thus following conclusions were derived from these findings: Evidence of self medication of cannabis because of pre existing Schizophrenia due to the mental health issues caused by schizophrenia related to negative symptoms may be a factor in continuous Cannabis consumption. There have been consistent longitudinal studies stating that cannabis precipitates schizophrenia and many other psychosis related symptoms in people who are vulnerable because of their family background. The rate of schizophrenia has remained stable or decreased with increases in cannabis use over the past few decades. Overall longitudinal studies conducted by Nemesis study from Holland and New Zealand have made these findings that conclude that cannabis can be considered a casual factor in schizophrenia. Research has found that alleged increases in cannabis use over past two decades have not affected increase in rate of schizophrenia. However vast number of people who consume cannabis have not developed schizophrenia and vast number of people who have schizophrenia have n ot got schizophrenia because of their cannabis consumption (Degenhardt et al, 2004). Conclusion Cannabis consumption may affect small percentage of population that is vulnerable socially and mentally. The pattern of cannabis use leading to clinically significant impairment or distress has manifested by a need for increased amounts of the substance to achieve intoxication or desired effect. That effect is then reduced by continuous use of the same amount of substance. Individuals then consume larger amount of substance to achieve that similar feeling and these persistent efforts start to affect the psyche of the individuals. Schizophrenia is more prevalent in individuals with poor socio economic background and history of substance abuse. Cannabis causes changes in neurotransmitter systems that make depressed mood more likely but greater evidence supports that this problem is due to individual behaviour pattern. Evidence from both hypotheses is limited and there needs to be well designed longitudinal studies including studies that examine cannabis use on older Australians to furt her narrow the relation between cannabis use and schizophrenia (Degenhardt et al, 2004).