The Database Environment IST - 331 Instructor: Victor Matos

Definitions Data: Meaningful facts, text, graphics, images, sound, video segments. Database: An organized collection of logically related data. Information: Data processed to be useful in decision making. Metadata: Data that describes data.

Figure 1-1a Data in Context

Figure 1-1b Summarized data

Disadvantages of File Processing Systems Data Dependence Data Redundancy (Duplication of data) Limited Data Sharing Lengthy Development Times Excessive Program Maintenance

Figure 1-2 Three file processing systems at Pine Valley Furniture

Advantages of the Database Approach Minimal Data Redundancy/Improved Consistency Data Integration Multiple Relationships

Database Management System A DBMS is a data storage and retrieval system which permits data to be stored non-redundantly while making it appear to the user as if the data is well-integrated.

Advantages of the Database Approach Data Independence/Reduced Maintenance Improved Data Sharing Increased Application Development Productivity Enforcement of Standards Improved Data Quality (Constraints) Better Data Accessibility/ Responsiveness Security, Backup/Recovery, Concurrency

Costs and Risks of the Database Approach New, Specialized Personnel Installation Management Cost and Complexity Conversion Costs Need for Explicit Backup and Recovery Organizational Conflict

Figure 1-3 Segment from enterprise data model

Figure 1-4a Order and Order_Line tables

Figure 1-4b Product and Customer tables

Figure 1-5 Client/server system for Pine Valley Furniture Company

Figure 1-6 Customer invoice (Pine Valley Furniture Company)

The Range of Database Applications Personal Database Workgroup Database Department Database Enterprise Database

Figure 1-7 Typical data from a personal computer database

Figure 1-8 Workgroup database with local area network

Figure 1-9 An example of departmental database (Personnel Department)

Figure 1-10 An enterprise data warehouse

Components of the Database Environment CASE Tools Repository Database Management System (DBMS) Database Application Programs User Interface Data Administrators System Developers End Users

Figure 1-11 Components of the database environment

Evolution of Database Systems Hierarchical and Network (Legacy) Relational Object-oriented Object-relational

Figure 1-12 Evolution of database technologies