Since JDK 6, DatabaseMetaData.getCrossReference contract is :
Retrieves a description of the foreign key columns in the given foreign key table that reference the primary key or the columns representing a unique constraint of the parent table (could be the same or a different table).
But the Oracle JDBC Driver executed query is :
SELECT
NULL AS pktable_cat,
p.owner as pktable_schem,
p.table_name as pktable_name,
pc.column_name as pkcolumn_name,
NULL as fktable_cat,
f.owner as fktable_schem,
f.table_name as fktable_name,
fc.column_name as fkcolumn_name,
fc.position as key_seq,
NULL as update_rule,
decode (f.delete_rule, 'CASCADE', 0, 'SET NULL', 2, 1) as delete_rule,
f.constraint_name as fk_name,
p.constraint_name as pk_name,
decode(f.deferrable, 'DEFERRABLE', 5, 'NOT DEFERRABLE', 7, 'DEFERRED', 6) deferrability
FROM
all_cons_columns pc,
all_constraints p,
all_cons_columns fc,
all_constraints f
WHERE 1 = 1
AND p.table_name = :1
AND f.table_name = :2
AND p.owner = :3
AND f.owner = :4
AND f.constraint_type = 'R'
AND p.owner = f.r_owner
AND p.constraint_name = f.r_constraint_name
AND p.constraint_type = 'P'
AND pc.owner = p.owner
AND pc.constraint_name = p.constraint_name
AND pc.table_name = p.table_name
AND fc.owner = f.owner
AND fc.constraint_name = f.constraint_name
AND fc.table_name = f.table_name
AND fc.position = pc.position
ORDER BY fktable_schem, fktable_name, key_seq
;
The right query to get foreign keys that reference a unique constraint is :
[...]
AND p.constraint_type in ('P', 'U')
[...]
Am I missing something ? Is there a workaround ?