Firebird SQL & Interbase list of all foreign keys

With that simple peace of code you can retrive the full list of all “FK” Foreign Key of an Interbase or Firebird DB.

SELECT rc.RDB$CONSTRAINT_NAME AS constraint_name,

i.RDB$RELATION_NAME AS table_name,

s.RDB$FIELD_NAME AS field_name,

i.RDB$DESCRIPTION AS description,

rc.RDB$DEFERRABLE AS is_deferrable,

rc.RDB$INITIALLY_DEFERRED AS is_deferred,

refc.RDB$UPDATE_RULE AS on_update,

refc.RDB$DELETE_RULE AS on_delete,

refc.RDB$MATCH_OPTION AS match_type,

i2.RDB$RELATION_NAME AS references_table,

s2.RDB$FIELD_NAME AS references_field,

(s.RDB$FIELD_POSITION + 1) AS field_position

FROM RDB$INDEX_SEGMENTS s

LEFT JOIN RDB$INDICES i ON i.RDB$INDEX_NAME = s.RDB$INDEX_NAME

LEFT JOIN RDB$RELATION_CONSTRAINTS rc ON rc.RDB$INDEX_NAME = s.RDB$INDEX_NAME

LEFT JOIN RDB$REF_CONSTRAINTS refc ON rc.RDB$CONSTRAINT_NAME = refc.RDB$CONSTRAINT_NAME

LEFT JOIN RDB$RELATION_CONSTRAINTS rc2 ON rc2.RDB$CONSTRAINT_NAME = refc.RDB$CONST_NAME_UQ

LEFT JOIN RDB$INDICES i2 ON i2.RDB$INDEX_NAME = rc2.RDB$INDEX_NAME

LEFT JOIN RDB$INDEX_SEGMENTS s2 ON i2.RDB$INDEX_NAME = s2.RDB$INDEX_NAME

WHERE rc.RDB$CONSTRAINT_TYPE = ‘FOREIGN KEY’

ORDER BY s.RDB$FIELD_POSITION