| Value | Meaning |
|---|---|
| Unknown0 | unspecified policy |
| None1 | not enforced policy |
| NoAction2 | return an error, no action taken |
| Restrict3 | same as @GDA_META_FOREIGN_KEY_NO_ACTION, not deferrable |
| Cascade4 | policy is to delete any rows referencing the deleted row, or update the value of the referencing column to the new value of the referenced column, respectively |
| SetNull5 | policy is to set the referencing column to NULL |
| SetDefault6 | policy is to set the referencing column to its default value |
Defines the filtering policy of a foreign key when invoked on an UPDATE or DELETE operation.