Cascade options

Select	To
Delete	Delete the selected record and any dependent records. For example, if a user is deleted from the USERINFO table, the associated records in the USERPROFILE table are also be deleted.
Clear	The key field linking the record in the secondary table is cleared out, but not the entire record in the secondary table. For example, if you delete a CONTACT record, the HISTORY records associated with that record are not deleted, just the link to that particular record.
Replace	When deleting a record, clear out the key field linking the record in a secondary table, but not the record itself. Replace the key field with another ID. For example, if a user is deleted from the USERINFO table, replace might be used to assign that person accounts to someone else.
Delete (Stop cascade)	Delete the selected record, but do not delete any dependent records. For example, if a user is deleted from the USERINFO table, the associated HISTORY records do not change at all.
Ignore (Don’t use in cascade)	When deleting a record, skip this table completely.

Delete

Delete the selected record and any dependent records.

For example, if a user is deleted from the USERINFO table, the associated records in the USERPROFILE table are also be deleted.

Clear

The key field linking the record in the secondary table is cleared out, but not the entire record in the secondary table.

For example, if you delete a CONTACT record, the HISTORY records associated with that record are not deleted, just the link to that particular record.

Replace

When deleting a record, clear out the key field linking the record in a secondary table, but not the record itself. Replace the key field with another ID.

For example, if a user is deleted from the USERINFO table, replace might be used to assign that person accounts to someone else.

Delete (Stop cascade)

Delete the selected record, but do not delete any dependent records.

For example, if a user is deleted from the USERINFO table, the associated HISTORY records do not change at all.

Ignore (Don’t use in cascade)

When deleting a record, skip this table completely.