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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 it’s 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)