what is Constraint? How many types of constraints in SQL ?
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Answer Posted / pramod tiwari,mba-it,lpu
SQL Constraints-
Constraints are used to limit the type of data that can go
into a table.
Constraints can be specified when a table is created (with
the CREATE TABLE statement) or after the table is created
(with the ALTER TABLE statement).
We will focus on the following constraints:
•NOT NULL
•UNIQUE
•PRIMARY KEY
•FOREIGN KEY
•CHECK
•DEFAULT
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