SQL Add Primary Key


Example

ALTER TABLE EMPLOYEES ADD pk_EmployeeID PRIMARY KEY (ID)

This will add a Primary key to the table Employees on the field ID. Including more than one column name in the parentheses along with ID will create a Composite Primary Key. When adding more than one column, the column names must be separated by commas.

ALTER TABLE EMPLOYEES ADD pk_EmployeeID PRIMARY KEY (ID, FName)