In conjunction with Association Rule, Association Type identifies the nature of the relationship between the current table and the target table as specified in the Accessed Table property. They allow a more precise meaning to be ascribed to an Access route than was previously possible with the Maximum Records and Default Action features, and are used by the Database Diagram Viewer to better show relationships.
There are several possible values:
Changes to Association Type and Rule may cause the Maximum Records and Default Action to automatically update.