Table with ForeignKey to table x - sql

Question

I've got an Oracle-DB with ~50 Tables.
Now, i'm looking for all tables with a foreign key to Table 'xyz'.
is there a way to do this?
greetings,
Lea

Answer 1

Foreign keys reference primary (or unique) keys, not tables. So first thing is to establish the primary key(s) for XYZ. Then we can look up the foreign keys which reference it.
select p.constraint_name
, p.constraint_type
, f.owner
, f.table_name
, f.constraint_name
from all_constraints p
left join all_constraints f
on ( f.r_constraint_name = p.constraint_name)
where p.table_name = 'XYZ'
and p.constraint_type in ('P', 'U')
and f.constraint_type = 'R'
I've done this as an OUTER JOIN so it will return something even if no tables reference a key on XYZ. Your table might be referenced by tables in other schemas. That's why I suggest using ALL_CONSTRAINTS rather than USER_CONSTRAINTS.

Answer 2

select fk.table_name from all_constraints fk , all_constraints pk
where
pk.table_name = 'XYZ'
and fk.constraint_type = 'R'
and fk.r_constraint_name = pk.constraint_name

Answer 3

It seems, that you can query User_Constraints view, something like
select distinct Table_Name
from User_Constraints
where Constraint_Type = 'R' and
R_Constraint_Name in (
select Constraint_Name
from User_Constraints
where Constraint_Type = 'P' and
Table_Name = Upper('xyz')) -- <- Your table name
order by Table_Name -- <- may be redundant

Answer 4

for sql try this :
SELECT K.TABLE_NAME ,
K.COLUMN_NAME ,
K.CONSTRAINT_NAME
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS C
JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS K ON C.TABLE_NAME = K.TABLE_NAME
AND C.CONSTRAINT_CATALOG = K.CONSTRAINT_CATALOG
AND C.CONSTRAINT_SCHEMA = K.CONSTRAINT_SCHEMA
AND C.CONSTRAINT_NAME = K.CONSTRAINT_NAME
WHERE C.CONSTRAINT_TYPE = 'FOREIGN KEY' /*FOR FOREIGN KEY U NEED TO REPLACE CONSTRAINT_TYPE WITH FOREIGN KEY*/
AND K.COLUMN_NAME IN ( SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS )