Use referential constraints to indicate relationships between columns of different tables. There are three specific types of referential constraints.
| Referential Constraint Type | DDL Definition | Does It Enforce Referential Integrity? | Level of Referential Integrity Enforcement |
|---|---|---|---|
| Referential constraint | REFERENCES WITH NO CHECK OPTION | No | None |
| Batch referential integrity constraint | REFERENCES WITH CHECK OPTION | Yes | Request |
| Referential integrity constraint | REFERENCES | Yes | Row |