Change Settings window

This window allows you to change the foreign key settings for check on commit, whether NULL values are allowed, and update and delete behavior.

This window has the following components:

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.

Simple Select this option to have a match occur for a row in the referencing table if at least one column in the key is NULL, or all the column values match the corresponding column values present in a row of the referenced table. This option is only available if Allow Null Values is selected.
Full Select this option to have a match occur for a row in the referencing table if all column values in the key are NULL, or if all of the column values match the values present in a row of the referenced table. This option is only available if Allow Null Values is selected.

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 Allow Nulls 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.

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.

Change Settings window

See also