Oracle..

WITH p AS
(SELECT c.table_name,
c.constraint_name,
o.object_id
FROM all_constraints c,
dba_objects o
WHERE constraint_type='P'
AND o.object_name =c.table_name
AND c.owner ='GDS_OWNER'
and o.owner = 'GDS_OWNER'
and o.object_type ='TABLE'
),
c AS
(SELECT c.table_name,
c.R_CONSTRAINT_NAME constraint_name,
o.object_id
FROM all_constraints c,
dba_objects o
WHERE constraint_type='R'
AND o.object_name =c.table_name
AND c.owner ='GDS_OWNER'
and o.owner = 'GDS_OWNER'
and o.object_type ='TABLE'
),
ORACLE_CONNET_BY_TEST AS
(SELECT DISTINCT p.object_id table_id,
0 parent_id ,
p.table_name
FROM p,
c WHERE c.table_name!=P.table_name
UNION ALL
SELECT DISTINCT c.object_id table_id,
p.object_id parent_id ,
c.table_name
FROM p,
c
WHERE c.constraint_name=p.constraint_name
),
T AS (SELECT LEVEL LVL,
TABLE_ID,
PARENT_ID,
LPAD(' ', 4 * (LEVEL - 1))
|| TABLE_NAME AS TABLE_NAME
FROM ORACLE_CONNET_BY_TEST
START WITH parent_Id = 0
CONNECT BY PRIOR TABLE_ID = PARENT_ID )
SELECT * FROM T --WHERE LVL=1


select * from dba_objects where object_name='CLM'