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 DBMS (Database Management System) 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 Credit card 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 Data entry & report Sales Files 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.

Data Redundancy

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