Re: Direct and indirect foreign key relationships in SQL or Pl/Sql

From: <Jared.Still_at_radisys.com>
Date: Fri, 20 Dec 2002 11:14:39 -0800
Message-ID: <F001.00520315.20021220111439@fatcity.com>

Here's one way.

It uses a temporary table, as a CONNECT BY cannot be done on the %_CONSTRAINTS view.

Jared

create test data

---

drop table t3;
drop table t2;
drop table t1;

create table t1 ( pk number );
create table t2 ( pk number, t1_pk number );

create table t3 ( pk number, t2_pk number ); create table t4 ( pk number, t3_pk number );

alter table t1 add constraint t1_pk
primary key(pk);

alter table t2 add constraint t2_pk
primary key(pk);

alter table t3 add constraint t3_pk
primary key(pk);

alter table t4 add constraint t4_pk
primary key(pk);

alter table t2 add constraint t2_t1_pk
foreign key(t1_pk)
references t1(pk);

alter table t3 add constraint t3_t2_pk
foreign key(t2_pk)
references t2(pk);

alter table t4 add constraint t4_t3_pk
foreign key(t3_pk)
references t3(pk);

---

• create temp table drop table r1;

create global temporary table r1
on commit delete rows
--create table r1
as
select

        c.table_name child


        , p.table_name parent

        , p.constraint_name

        , c.constraint_name fk_constraint

        , c.delete_rule

from dba_constraints c, dba_constraints p where 1=0
/

insert into r1
select *
from
(
select

        c.table_name child


        , p.table_name parent

        , p.constraint_name

        , c.constraint_name fk_constraint

        , c.delete_rule

from dba_constraints c, dba_constraints p where c.owner = 'JKSTILL'
--and c.table_name like 'T%'

and c.constraint_type in ('R')
and c.status = 'ENABLED'
and p.owner = c.r_owner
and p.constraint_name = c.r_constraint_name

) a
/

---

• report

col child format a10
col parent format a20
col pad format a20
col constraint_name format a30
col r_constraint_name format a30
col tlevel noprint

set line 120

select

        tlevel


        , parent

        , constraint_name

        , child

        , fk_constraint

        , delete_rule

from (
        select
                level tlevel
                , lpad(parent, level*3) parent
                , constraint_name
                , child
                , fk_constraint
                , delete_rule
        from r1
        start with parent = 'T1'
        connect by prior child = parent

)
order by tlevel
/

"Krishnaswamy, Ranganath" <Ranganath.Krishnaswamy_at_blr.hpsglobal.com> Sent by: root_at_fatcity.com
 12/18/2002 11:13 PM
 Please respond to ORACLE-L  

        To:     Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
        cc: 
        Subject:        Direct and indirect foreign key relationships in SQL or Pl/Sql

Hi all,

                 How do I find out the direct and indirect foreign key 

relationships?
Say, for example there are four tables A, B, C and D of which A is the parent table and B, C and D are child tables. Say B and C are related to A
directly and D is related to A through C. How do I find out this indirect relationship apart from the direct relationships? Any help in this regard is very much appreciated.

Thanks and Regards,

Ranganath  

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Author: 
  INET: Jared.Still_at_radisys.com

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Received on Fri Dec 20 2002 - 13:14:39 CST