How to Set or Change the Primary Key in a Microsoft Access Database

Primary keys are unique record identifiers that MS Access uses when retrieving information for a query or a report. With primary keys, you can join tables in relationships so that you can query both of them at once. These instructions are for Access 97.

Things You'll Need

• Microsoft Access

Instructions

1. Open a table in Design view.

2. Click the Row Selector for each field you want to set for the primary key. The Row Selector is the small box that allows you to select an entire row.

3. Click on the Primary Key icon in the toolbar, or select Primary Key from the Edit menu.

4. If you've selected a field for a Primary Key that already contains data or returns a null value, MS Access will not allow you to create a primary key.

5. If desired, you can edit the data so it's no longer duplicated.

Tips & Warnings

• Windows users can select multiple fields by holding the Control key and then clicking in each field to be used.

• See the Related eHow "Determine Which Primary Key Type to Use in Microsoft Access" for more about using primary keys.