A database is a collection of data in which we can manipulate data and store them in various way. For example you have to store your name, age and school you previously attended so that data would be stored in database.
Related software by which we can access data manage them, creation and manipulation done in known as DATABASE MANAGEMENT SYSTEM ( DBMS ).
How it is diffeerent from file system –
- File system have problem of Redundant data (duplicity) We can make data consistant by removing duplicity.
- File system have Integrity problem which tends to have multiple file format, duplicate meta data so that we need to write new program for accessing each file.
- Data isolation is again a main problem in file sytem in which we have multiple file format.
Invalid data may be inserted by a human error or a bug. - Failure between the accessing of data may leave data in inconsistant state with partial update carried out.
- Concurrent access by multiple user can lead to slow performance and redundat data or inconsistancy.
Level Of Abstraction – Tells us how data is stored and accessed, let examine figure below –
ADVANTAGE –
Controlling data redundancy
Data consistancy
Data Integity
Data security
Backup
Data independence
Schema – Overall structure of database
Logical schema – Such as type of data, size, attribute
Physical Schema – Hardware
In next post we will discuss about the DATA MODELS –
C#ODE Studio 