Database Management System (DBMS)

nCollection of interrelated data

nSet of programs to access the data

nDBMS contains information about a particular 

  enterprise

nDBMS provides an environment that is both 

convenient and efficient to use.

nDatabase Applications:

HBanking: all transactions

HAirlines: reservations, schedules

HUniversities:  registration, grades

HSales: customers, products, purchases

HManufacturing: production, inventory, orders, supply chain

HHuman resources:  employee records, salaries, tax deductions

nDatabases touch all aspects of our lives

Purpose of Database System

* In the early days, database applications were 

   built on top of file systems

* Drawbacks of using file systems to store data:

HData redundancy and inconsistency

4Multiple file formats, duplication of information in different files

HDifficulty in accessing data

4Need to write a new program to carry out each new task

HData isolation — multiple files and formats

HIntegrity problems

4Integrity constraints  (e.g. account balance > 0) become part of program code

4Hard to add new constraints or change existing ones