notes of database concepts by preeti arora for class 11th
Answers
database operations
to maintain huge databases,we need certain operations which help in maintaining the data in the database efficiently.
the most commonly used operations performed on the databases are:
a insertion- to add new data into the database.e.g to add new phone number into the telephone directory.
b selection-to view or retrieve the stored data.e.g to view a telephone number of a particular person from the telephone directory.
c updation-to modify or edit the existing data.e.g suppose the phone number of a particular person is changed,so we have to modify the telephone directory by replacing his old phone number with a new phone number.
d Deletion-to remove or delete the existing data from the database.e.g suppose an employee has left the organization,so his record should be deleted from the employee database of the organization .
e sorting- to range the data in a desired order(ascending/descending).e.g in employee database of an organization,records should be arranged in an alphabetical order for easy and fast retrieval.
