UNIQUE constraint The UNIQUE constraint uniquely identifies each record in a database table. The UNIQUE and PRIMARY KEY constraints both provide a guarant…

Constraint ( NOT NULL ) The NOT NULL constraint enforces a column to NOT accept NULL values. The NOT NULL constraint enforces a field to always contain a v…

Select Into   The SELECT INTO statement selects data from one table and inserts it into a different table. The SELECT INTO statement is most often used to c…

Classes Class   is a user defined data type just like   structures ,   but with a difference It also has three sections namely   private ,   public   and   prot…