i) Data integration

  • Integration of the data from several different systems into one database system which is shared by several users involves ensuring

  • that there is no redundancy (or very little) of data.

  • The aim is to have one database storing one logical item of data in one place which can be accessed by a range of information systems.

ii) Data abstraction

  • Data abstraction is the process by which a database attempts to represent the properties of objects in the real world.

  • A database records the relevant details required to support some organisational activity, it does not record all the details thus the database is an abstraction of the real world.

  • The level of abstraction varies with different commercial databases.

iii) Data independence

  • The aim is to achieve a situation where data organisation is transparent to the users or application programs which feed off the data.

  • Thus, a change to some part of the physical database does not affect the application programs and also a change to the application programs does not affect the physical structure of the database.

  • Physical and logical databases are independent.

iv) Data security

  • To help ensure the integrity of the database, access to the database is restricted.

  • Define a set of authorised users who have access to all or parts of the database.