SQL ALTER TABLE statement have used to add and drop primary key of a table.

In this page we are going to discuss about the usage of SQL ALTER TABLE statement to add and drop CHECK CONSTRAINT of column(s) of a table.

In this page we are going to discuss about the usage of SQL ALTER TABLE statement is used to add a constraint for a column and also drop an existing constraint of a column from a table if the column exists in the table.

In this page it is going to be discussed that, how SQL FOREIGN KEY CONSTRAINT is used with primary key column list in a CREATE TABLE statement.

In this page we are going to discuss, how FOREIGN KEY CONSTRAINT can be used without specifying the primary key column(s).

In this page we are going to discuss the usage of FOREIGN KEY CONSTRAINT without using the 'foreign key' key word.

The SQL FOREIGN KEY CONSTRAINT is used to ensure the referential integrity of the data in one table to match values in another table

In this page we have discussed usage of SQL DEFAULT CONSTRAINT and usage of SQL CHECK CONSTRAINT while creating a table.

The SQL DEFAULT CONSTRAINT provides a default value when specified none for a column.

In this page we are going to discuss about the usage of OR and AND operator along with the CHECK CONSTRAINT.