How to Understand Cascading Updates or Cascading Deletes in Microsoft Access

You can automatically update or delete related records from various MS Access tables by using cascading updates or cascading deletes. These instructions are for Access 97.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Microsoft Access

1. Understand that cascading updates or cascading deletes are used to overrule referential integrity rules while retaining relationship integrity. These conditions only apply to relationships in which referential integrity is enforced.

2. Know that by selecting Cascade Update Related Fields checkbox when you are defining a relationship, a subsequent change to a record will automatically generate an update in all related records.

3. Understand that by selecting Cascade Delete Related Fields checkbox when you are defining a relationship, a subsequent deletion of a record will automatically cause a deletion of all related records.

Tips & Warnings

• Referential integrity ensures that your related data is clean - for example, that you don't have more than one record in a table with the same primary key. See "Understand Referential Integrity in Microsoft Access," under Related eHows for more on the subject.
• If you use cascading deletes and delete records using a delete query, MS Access deletes all related records without issuing a warning.