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 primary key of a table.

In this page we are going to discuss, how SQL FOREIGN KEY CONSTRAINT can be used on more than one columns with primary key column list in a CREATE TABLE statement.

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 SQL PRIMARY KEY CONSTRAINT along with the CREATE TABLE statement for two or more columns.

This SQL PRIMARY KEY CONSTRAINT are a combination of a NOT NULL constraint and a UNIQUE constraint.

The SQL PRIMARY KEY is a column in a table which must contain a unique value which can be used to identify each and every row of a table uniquely.

In this page we are going to discuss about such a join, which is made up by using two tables which contain a composite PRIMARY KEY and FOREIGN KEY.

In this page we are going to discuss the usage of two or more tables. in a joining with single column PRIMARY KEY and FOREIGN KEY.