Problem 11 , 12
TextBook: database systems a practical approach to design implementation and management 6th
Chapter Summary . The Database Management System (DBMS) is now the underlying framework of the information system and has fundamentally changed the way in which many organizations operate. The database system remains a very active research area and many significant problems remain. . The predecessor to the DBMS was the file-based system, which is a collection of application programs that perform services for the end-users, usually the production of reports. Each program defines and manages its own data. Although the file-based system was a great improvement over the manual filing system, it still has significant problems, mainly the amount of data redundancy present and program-data dependence. The database approach emerged to resolve the problems with the file-based approach. A database is a shared collection of logically related data and a description of this data, designed to meet the information needs of an organization. A DBMS is a software system that enables users to define, create, maintain, and control access to the database. An application program is a computer program that interacts with the database by issuing an appropriate request (typically a SQL statement) to the DBMS. The more inclusive term database system is used to define a collection of application programs that interact with the database along with the DBMS and database itself. All access to the database is through the DBMS. The DBMS provides a Data Definition Language (DDL). which allows users to define the database, and a Data Manipulation Language (DML), which allows users to insert, update, delete, and retrieve data from the database. . The DBMS provides controlled access to the database. It provides security, integrity, concurrency and recovery control, and a user-accessible catalog. It also provides a view mechanism to simplify the data that users have to deal with . The DBMS environment consists of hardware (the computer), software (the DBMS, operating system, and appli procedures, and people. The people include data and database administrators, database cations programs), data, designers, application developers, and end-users. . The roots of the DBMS lie in file-based systems. The hierarchical and CODASYL systems represent the first MS (Information Management System) and the generaion of DBSs The hierarchical model is typified by IMS Information Management ystem) and the I Study the DreamHlome case study presented in Section14 and Appendx A (a) In what ways would a DBMS help this organization? b) What do you think are the main objects that need to be represented in the database? () What relationships do you think exist between these main objects? For each of the objects, what details do you think need to be stored in the database? (d) (e) What queries do you think are required? 12 Study the Wellmeadows Hospital case study presented in Appendix B.3. (a) In what ways would a DBMS help this organization? (b) What do you think are the main objects that need to be represented in the database? c) What relationships do you think exist between these main objects? (d) For each of the objects, what details do you think need to be stored in the database? (e) What queries do you think are required? mort imnortant achantages for the use of a DBMS for a company Store), both developed in the mid-19605. network or cODASYL model by IDS (integrated Data PRC tional model, proposed by E. F. Codd in 1970, represents the second generation of DBMSs, It has al effect on the DBMS community and there are now over one hundred relational DBMS generation of DBMSs are represented by the Object-Relational DBMS and the Object-Oriented DBM 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 DBMSs. The thirc and higher impact of a failure. Chapter Summary . The Database Management System (DBMS) is now the underlying framework of the information system and has fundamentally changed the way in which many organizations operate. The database system remains a very active research area and many significant problems remain. . The predecessor to the DBMS was the file-based system, which is a collection of application programs that perform services for the end-users, usually the production of reports. Each program defines and manages its own data. Although the file-based system was a great improvement over the manual filing system, it still has significant problems, mainly the amount of data redundancy present and program-data dependence. The database approach emerged to resolve the problems with the file-based approach. A database is a shared collection of logically related data and a description of this data, designed to meet the information needs of an organization. A DBMS is a software system that enables users to define, create, maintain, and control access to the database. An application program is a computer program that interacts with the database by issuing an appropriate request (typically a SQL statement) to the DBMS. The more inclusive term database system is used to define a collection of application programs that interact with the database along with the DBMS and database itself. All access to the database is through the DBMS. The DBMS provides a Data Definition Language (DDL). which allows users to define the database, and a Data Manipulation Language (DML), which allows users to insert, update, delete, and retrieve data from the database. . The DBMS provides controlled access to the database. It provides security, integrity, concurrency and recovery control, and a user-accessible catalog. It also provides a view mechanism to simplify the data that users have to deal with . The DBMS environment consists of hardware (the computer), software (the DBMS, operating system, and appli procedures, and people. The people include data and database administrators, database cations programs), data, designers, application developers, and end-users. . The roots of the DBMS lie in file-based systems. The hierarchical and CODASYL systems represent the first MS (Information Management System) and the generaion of DBSs The hierarchical model is typified by IMS Information Management ystem) and the I Study the DreamHlome case study presented in Section14 and Appendx A (a) In what ways would a DBMS help this organization? b) What do you think are the main objects that need to be represented in the database? () What relationships do you think exist between these main objects? For each of the objects, what details do you think need to be stored in the database? (d) (e) What queries do you think are required? 12 Study the Wellmeadows Hospital case study presented in Appendix B.3. (a) In what ways would a DBMS help this organization? (b) What do you think are the main objects that need to be represented in the database? c) What relationships do you think exist between these main objects? (d) For each of the objects, what details do you think need to be stored in the database? (e) What queries do you think are required? mort imnortant achantages for the use of a DBMS for a company Store), both developed in the mid-19605. network or cODASYL model by IDS (integrated Data PRC tional model, proposed by E. F. Codd in 1970, represents the second generation of DBMSs, It has al effect on the DBMS community and there are now over one hundred relational DBMS generation of DBMSs are represented by the Object-Relational DBMS and the Object-Oriented DBM 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 DBMSs. The thirc and higher impact of a failure
