Displaying foreign key relationships in Oracle 9i

Question

Hello All. Is there a command in oracle 9i that displays the foreign keys of a table and also the table that those foreign keys reference?

I was searching, did not find anything but i found an equivalent command that works with MySql which is SHOW CREATE TABLE

Is there an equivalent command for this within oracle's SQL?

I appreciate your response, however I thought there was a really short way of doing this like MySql.

Answer 1

This may do what you want, it uses Oracle system views. I don't have an Oracle instance handy to test it, however.

SELECT fk.owner, fk.constraint_name, fk.table_name, fc.column_name,
  pk.owner, pk.constraint_name, pk.table_name, pc.column_name
FROM all_constraints fk
 JOIN all_cons_columns fc ON (fk.owner = fc.owner AND fk.constraint_name = fc.constraint_name)
 JOIN (all_constraints pk
   JOIN all_cons_columns pc ON (pk.owner = pc.owner AND pk.constraint_name = pc.constraint_name)) 
 ON (fk.r_owner = pk.owner AND fk.r_constraint_name = pk.constraint_name
   AND fc.position = pc.position)
WHERE fk.constraint_type = 'R' AND pk.constraint_type IN ('P', 'U')
  AND fk.owner = '<schema>' AND fk.table_name = '<table>';

Answer 2

You could start by listing all of the constraints for the table along with any referenced constraint on other tables:

SELECT
     acc.table_name
    ,acc.column_name
    ,acc.constraint_name
    ,ac.r_constraint_name AS referenced_constraint
FROM all_cons_columns acc
INNER JOIN all_constraints ac ON (acc.constraint_name = ac.constraint_name)
WHERE acc.table_name = UPPER('your_table_here');

If you have sensible naming conventions for your constraints it should be possible to identify which are the foreign keys, an 'FK' prefix/suffix is typical.

Answer 3

Here's another answer: The dbms_metadata package has a function that can return the DDL for a table definition.

SELECT dbms_metadata.get_ddl('TABLE', '<table>', '<schema>') FROM dual;

This package has apparently been available since Oracle 9.2

http://download-west.oracle.com/docs/cd/B10501_01/appdev.920/a96612/d_metada.htm#1656

Answer 4

If you need the DDL for the foreign keys in the future, then here is the answer in advance :)

select 
  DBMS_METADATA.GET_DEPENDENT_DDL('REF_CONSTRAINT' ,atb.table_name, atb.owner) 
from 
  all_tables atb, all_constraints ac
where 
  atb.owner = ac.owner and
  ac.constraint_type = 'R' and
  ac.table_name = atb.table_name and
  atb.owner = 'YOURSCHEMA';