Database Management Systems Chapter 1

Introduction What is a database? What is a database management system (DBMS)? Remind me to tell you about this: http://msdn.microsoft.com/vstudio/express/vwd/ Database – collection of data stored in a standardized format Designed to be used by multiple users DISCUSS Examples: (1) The university’s student files – demographic data, grades, test scores, (2) Small business (ie., Kaikodo restaurant – suppliers – names and addresses, wine list, etc.) DBMS – software that defines a database, stores the data, supports a query language, produces reports, and creates data entry screens Access Advantages: inexpensive, readily available, relatively robust implementation of SQL, easy to use, lots of books and manuals for reference. Disadvantages: not designed to handle a large number of users (best for small businesses), security administration is more cumbersome, database administration tools lack the sophistication of higher-end products Oracle Advantages: extremely powerful, used in large comprehensive applications, designed for use by many users all at the same time, works well in the client-server environment. Disadvantages: tools are complex, database administration is complex SQL Server (part of the Microsoft set of MSDN tools which includes SQL server, and DB2) Bridges gap between the two. Simpler to use than oracle but more powerful than Access.

Database development Challenges Conserving space Retrieving data rapidly Sharing data Providing backup and recovery

Application Development Feasibility – identify scope, costs, and schedule Analysis – gather information from users Design – define tables, relationships, forms, reports Development – create forms, reports, and help; test Implementation – transfer data, install, train, review

Components of DBMS Database engine Data dictionary Query processor Report writer Forms generator Application generator Communication and Integration facilities Security facilities Database engine – the heart of the DBMS – it is responsible for storing, retrieving, and updating the data. Also responsible for enforcing business rules Data dictionary – holds the definitions of all the data tables. It describes the type of data that is being stored (stored as a set of system tables. Access keeps the list of all the tables in a hidden system tables called MsysObjects Query processor – Enables developers and users to store and receive data. Queries are generally derived from business questions. Report writer – provides users with summary of data. Report writer can be integrated with DBMS or stand alone Forms generator – AKA input screen. Helps the developer create input forms. Application generator – An application is a collection of forms and reports designed for a specific user task. A good DBMS contains an application generator to develop menus and toolbars and help systems Communication and Integration faculties – facility for connecting machines and components so that data can be shared. (Client/Server architecture) Security facilities – backup, restore, security authorizations

Advantages of DBMS Minimal data redundancy Data consistency Integration of data Sharing of data Enforcement of standards Ease of application development Uniform security, privacy, and integrity Data independence Minimal data redundancy – only load the data once. This cuts down on errors and time Data consistency – data the same in different reports etc. because it is only loaded once. DISCUSS OLD SYSTEM (with University files) and new Distributed DB systems. Student number Student address (billing was parents, student life was on-campus) Different files that didn’t talk – student demo, grades, health, billing, admissions

Brief History of DBMS Hierarchical databases Network databases Relational databases Object-oriented databases

Object Oriented For more information visit this website: http://java.sun.com/docs/books/tutorial/java/concepts/index.html