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Introduction to Database. CIS458.101 Chapter 1 Sungchul Hong. Database System. The most important development in the field of software engineering. Database serve as the foundation for considerable progress in the basic science fields ranging from computing to biology. Introduction.
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Introduction to Database CIS458.101 Chapter 1 Sungchul Hong
Database System • The most important development in the field of software engineering. • Database serve as the foundation for considerable progress in the basic science fields ranging from computing to biology.
Introduction • Database • A collection of related data. • DBMS (Database Management System) • The software that manages and controls access tot the database. • Database application • A program that interacts with the database at some point in its execution.
Examples of Databases • Supermarket • Inventory • Customer service • Credit card • Booking a ticket at the travel agents • Using the local library • University
Traditional File-Based Systems • Each program defines and manages its own data. • Separation and isolation of data • Duplication of data • Data dependence • Incompatibility of files • Fixed queries of application program
Database Approach • A shared collection of logically related data, and a description of this data, designed to meet the information needs of an organization. • System catalog (data dictionary) • Program-data independence.
File-Based System File handling routines Data entry & report File definition Sales Files
The Database Management System (DBMS) • A software system that enables users to define, create, maintain, and control access to the database. • Data Definition Language(DDL) • Data Manipulation Language (DML) • Structured Query Language (SQL) • Views • Level of security, customization, provide consistent structure
Components of the DBMS Environment • Hardware • Client-server architecture • Backend, front end • Software • DBMS, application programs, SQL • Data • Operational data, meta data • Procedure • Instructions and rules • People
Roles in the Database Environment • Data Administrator (DA) • Responsible for the management of the data resource including database planning, development and maintenance of standards, policies, and procedures, and conceptual/logical database design. • Database Administrator (DBA)-more technical • Responsible for the physical realization of the database, including physical database design and implementation, security and integrity of the application users.
Roles in the Database Environment (2) • Database Designer • Logical database designer • Identifying the data, relationship between the data, and the constraints on the data. • Business rules. • Physical database designer • Mapping the logical database design into a set of tables and integrity constraints. • Selecting specific storage structures • Designing security measures required on the data
Roles in the Database Environment (3) • Application Developer • Provide the required functionality for the end-users. • End-Users • Naïve users • Sophisticated users.
Advantages of DBMS • Control of data redundancy • Data consistency • More information from the same amount of data • Sharing of data • Improved data integrity • Improved security • Enforcement of standards
Advantages of DBMS (2) • Economy of scale • Balance of confliction requirements • Improved data accessibility and responsiveness • Increased productivity • Improved maintenance through data independence • Increased concurrency • Improved backup and recovery services
Disadvantages of DBMS • Complexity • Size • Cost of DBMS • Additional hardware costs • Cost of conversion • Performance • Higher impact of a failure
History of DBMS • Apollo moon-landing project (1960s) • GUAM (Generalized Update Access Method) • Hierarchical structure • IMS (Information Management System) (mid 1960s) • Serial storage • device (Tape recorder) • IDS (Integrated Data Store) (mid 1960s) • Network DBMS • CODASYL (Conference on Data Systems Languages)
History of DBMS • DBTG (Data Base Task Group) – 1967 • Relational Model – E. F. Codd, 1970 • R • SQL • DB2, SQL/DS, Oracle • INGRES II, Informix, Access, FoxPro, Paradox, Interbase, and R:Base • ER model – Chen, 1979 • Semantic data modeling • Object-Oriented DBMS, Object-Relational DBMS