This dialog allows you to change a foreign key's settings for check on commit, whether NULL values are allowed, and update and delete behavior.
The Change Settings dialog has the following components:
Check only on a commit Forces the database to wait for a COMMIT before checking the integrity of the foreign key, overriding the setting of the WAIT_FOR_COMMIT database option.
Allow null values Determines whether the foreign key columns allow NULL values. To use this option, the foreign key columns must all have Allow Nulls set to Yes.
Update action Uses one of the following settings to define the behavior of the table when a user tries to update data.
Not permitted Prevents updates of the associated primary table's primary key value if there are no corresponding foreign keys.
Cascade values Updates the foreign key to match a new value for the associated primary key.
Set values to null Sets all the foreign key values that correspond to the updated primary key of the associated primary table to NULL.
Set values to default Sets foreign key values that match the updated or deleted primary key value to values specified in the DEFAULT clause of each foreign key column. To use this option, the foreign key columns must all have default values.
Delete action Uses one of the following settings to define the behavior of the table when a user tries to delete data.
Not permitted Prevents deletion of the associated primary table's primary key value if there are no corresponding foreign keys in the table.
Cascade values Deletes the rows from the table that match the deleted primary key of the associated primary table.
Set values to null Sets all the foreign key values in the table that correspond to the deleted primary key of the associated primary table to NULL. To use this option, the foreign key columns must all have Allows Null set to Yes.
Set values to default Sets foreign key values that match the updated or deleted primary key value to values specified in the DEFAULT clause of each foreign key column. To use this option, the foreign key columns must all have default values.