Advanced Database System 1.1 Introduction A database system ⇒ a computerized record-keeping system Operations: 1) adding new, empty files to the database 2) inserting data into existing files 3) retrieving data from existing files 4) deleting data from existing files 5) changing data in existing files 6) removing existing files from the database (See Fig. 1.1, 1.2, & 1.3) Advanced Database System

Advanced Database System

Advanced Database System

1.2 What is a Database System ? Advanced Database System

1.2 What is a Database System ? (cont.) Four components: 1) data ⇒ integrated & shared (See Fig. 1.5) 2) hardware ⇒ the second storage volumes, the processors, & main memory 3) software ⇒ database management system (DBMS) 4) users ⇒ application programmers, end users, & database administrator (DBA) Advanced Database System

Advanced Database System 1.3 What is a Database ? A database ⇒ persistent data Entities & Relationships Example: E/R diagram (See Fig. 1.6) A number of points: 1) ternary relationship 2) one relationship involving just one entity type 3) more relationships between entities Properties Data and data models Advanced Database System

Advanced Database System

Advanced Database System 1.4 Why Database ? Centralized control of data Data administration (manager) Database administration (technician) Benefits of the database approach The data can be shared Redundancy can be reduced Inconsistency can be avoided Transaction support can be provided Integrity can be maintained Security can be enforced Conflicting requirements can be balanced Standards can be enforced Advanced Database System

Advanced Database System 1.5 Data Independence The immunity of applications to change in physical representation and access technique Stored field, stored record, stored file (See Fig. 1.7) Advanced Database System

1.6 Relational Systems and Others The oldest systems: Inverted list Hierarchic Network Relation systems: DB2, Ingres II, Informix Dynamic Server, Microsoft SQL server, Oracle 9i, Sybase Adaptive Server (See Fig. 1.8) Object systems: GemStone, Versant ODBMS Advanced Database System

Advanced Database System

Advanced Database System The End. Advanced Database System