| conname | name | | Constraint name (not necessarily unique!) |
| connamespace | oid | pg_namespace.oid | The OID of the namespace that contains this constraint
|
| contype | char | | 'c' = check constraint,
'f' = foreign key constraint,
'p' = primary key constraint,
'u' = unique constraint
|
| condeferrable | boolean | | Is the constraint deferrable? |
| condeferred | boolean | | Is the constraint deferred by default? |
| conrelid | oid | pg_class.oid | The table this constraint is on; 0 if not a table constraint |
| contypid | oid | pg_type.oid | The domain this constraint is on; 0 if not a domain constraint |
| confrelid | oid | pg_class.oid | If a foreign key, the referenced table; else 0 |
| confupdtype | char | | Foreign key update action code |
| confdeltype | char | | Foreign key deletion action code |
| confmatchtype | char | | Foreign key match type |
| conkey | int2[] | pg_attribute.attnum | If a table constraint, list of columns which the constraint constrains |
| confkey | int2[] | pg_attribute.attnum | If a foreign key, list of the referenced columns |
| conbin | text | | If a check constraint, an internal representation of the expression |
| consrc | text | | If a check constraint, a human-readable representation of the expression |
