Introduction to Database
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.
• 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
Traditional File-Based Systems
• Each program defines and manages its own
• 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
• System catalog (data dictionary)
• Program-data independence.
File-Based System
Sales Files
The Database Management
System (DBMS)
• A software system that enables users to define,
create, maintain, and control access to the
• Data Definition Language(DDL)
• Data Manipulation Language (DML)
– Structured Query Language (SQL)
• Views
– Level of security, customization, provide consistent
Components of the DBMS
• 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
• 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 endusers.
• 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
Cost of DBMS
Additional hardware costs
Cost of conversion
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
– Serial storage
– device (Tape recorder)
• IDS (Integrated Data Store) (mid 1960s)
– Network DBMS
• CODASYL (Conference on Data Systems
History of DBMS
• DBTG (Data Base Task Group) – 1967
• Relational Model – E. F. Codd, 1970
– R
– 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

Introduction to Database