PRIMARY KEYS

Hi George

Thank you for your question

Multiple or compound keys are used in place of an autonumber field, where there is no one existing field that is unique to individual records.

For example if you had a staff database with no unique fields you might decide to use a key compounded out of first name, second name and date of birth fields

The important consideration would be the uniquness of each combination. In the above example the developer would have to consider the likelihood of two people sharing the same first and second names as well as a date of birth

Hope this helps

Regards

Stephen