Introduction to Databases

1
Chapter 1

• Introduction to Databases

2
Agenda

• File-based Systems
• History of Database
• Database Management Systems (DBMS)

3
File-based Definition

• Program defines and manages its own data

4
Limitations of File-based

• Separation and isolation
• Duplication
• Program data dependence
• Fixed queries
• Proliferation of application programs

5
History of Database Systems

• First generation
• Hierarchical model
• Information Management System (IMS)
• Network model
• Conference on Data System Languages (CODASYL)
• Data Base Task Group (DBTG)
• Limitation
• Complex program for simple query
• Minimum data independence
• No theoretical foundation
• Second generation
• Relational model
• E. R. Codd
• DB2, Oracle
• Limitation
• Limited data modeling
• Third generation
• Object-relational DBMS
• Object-oriented DBMS

6
Database

• Definition
• A collection of self-describing and integrated
  data files
• System catalog
• Meta data
• Data dictionary
• Overhead data
• Data abstraction

7
Database Management System Facility

• Data definition language (DDL)
• Data manipulation language (DML)
• Structured query language (SQL)
• Security system
• Integrity system
• Concurrency control system
• Backup recovery system
• View mechanism

8
DBMS Environment

• Hardware
• Client-server architecture
• Software
• dbms, os, network, application
• Data
• Schema, subschema, table, attribute
• People
• Data administrator database administrator
• Database designer logical physical
• Application programmer
• End-user naive sophisticated
• Procedure
• Start, stop, log on, log off, back up, recovery

9
Advantages of DBMS

• Control redundancy
• Consistency
• Integrity
• Security
• Concurrency control
• Backup recovery
• Data standard
• More information
• Data sharing conflict control
• Productivity accessibility
• Economy of scale
• Maintenance

10
Limitations of DBMS

• Complexity
• Size
• Cost
• Software
• Hardware
• Conversion
• Performance
• Vulnerability

11
Points to Remember

• File-based Systems
• History of Database
• Database Management Systems (DBMS)

12
Assignment

• Review Chapter 1
• Read appendix C
• Turn in your group list (due 9/18/07) before
  class starts (1 point for on time roster, 0 for
  late one)