Primary Keys (Visual Database Tools)

A primary key constraint ensures no duplicate values are entered in particular columns and that NULL values are not entered in those columns. You can use primary key constraints to enforce uniqueness as well as referential integrity. For example, the au_id column uniquely identifies each author stored in the authors table.

You create primary key constraints in Table Designer.

Note

Some databases have different functionality for primary key constraints. Consult your database documentation for details about how your database works with primary key constraints.

For information about	See
Enforcing uniqueness for values entered in specified columns	How to: Create Primary Keys
Changing the column order, index name, clustered option, or fill factor	How to: Modify Primary Keys
Copying column properties from a primary key column to a foreign key column to relate the two columns	How to: Create Relationships Between Tables
Removing the requirement for uniqueness for the values entered in a column	How to: Delete Primary Keys

See Also

Reference

Indexes/Keys Dialog Box

Other Resources

Working with Keys

Working with Relationships