Introduction to Databases

Basic Database Concepts

What is a Database?
Enterprises run on data.
Here is a typical set of data for running a business.


A database can be defined as "A collection of related data stored on a computer".
Data : a recorded fact with an implicit meaning.
To have a meaning, all data items must have a label and a value.

Meaningless Data: 132 789-5421 36.75
Meaningful Data: Stock Level 132
Telephone_No 789-5421 Price 36.75


Data is stored in files.

Files

A file is "a collection of records with a common theme".

e.g. Customer Records, Student Records, Stock Records

A record consists of fields of data.The labels given to fields renders the data within them meaningful.

Customer Record :
Number
Name
Address
Telephone No
Credit Rating


A computer file is stored on a secondary storage device (typically disk), rendering its data accessible to a variety of programs.
Simple File Processing Systems vs Database Systems

A simple ...