|Microsoft Access 97 and 2000
In Access, you can base a primary key on more than one field. For example, a multiple-field primary key is useful if you have two tables in which one record in either table can relate to many records in the other table. To implement a many-to-many relationship between these tables, you create a third table and add the primary keys from each of the other two tables to this table. Then you can create a primary key composed of the fields that correspond to the primary keys in the other two tables.
To create a primary key based on more than one field
- Open the table in Design view.
- Hold down the CRTL key and click the row selector for each field that you want to include in the primary key.
- Click Primary Key on the toolbar.
For more information, type set or change the primary key in the Office Assistant or on the Answer Wizard tab in the Help window, and then click Search.