[askdba] Re: Strange behavior
- From: Regis Biassala <Regis.Biassala@xxxxxxxxxx>
- To: askdba@xxxxxxxxxxxxx
- Date: Mon, 4 Oct 2004 14:48:40 +0100
Hi Justin,
I was debugging an installtion script switch had this problem.
Then I could not understand why Oracle did not prevent this from happening.
So I tested it against Oracle, Mssql and Db2.
The only RDBMS preventing this behavior is DB2....
Regis
-----Original Message-----
From: askdba-bounce@xxxxxxxxxxxxx [mailto:askdba-bounce@xxxxxxxxxxxxx] On
Behalf Of Justin Cave (DDBC)
Sent: 02 October 2004 00:55
To: askdba@xxxxxxxxxxxxx
Subject: [askdba] Re: Strange behavior
Perhaps I am missing something obvious, but what is the point of
creating two foreign key constraints that would enforce the integrity
constraint? =20
Justin Cave <jcave@xxxxxxxxxxx>
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC
-----Original Message-----
From: askdba-bounce@xxxxxxxxxxxxx [mailto:askdba-bounce@xxxxxxxxxxxxx]
On Behalf Of Regis Biassala
Sent: Friday, October 01, 2004 8:01 AM
To: askdba@xxxxxxxxxxxxx
Subject: [askdba] Strange behavior
I've tested this against: oracle8i,9i,10g and MSSQL 2000, it is behaving
exactly the same...
I came across this while debugging an installation scripts...
See test below:
SQL> create table parent (id int not null primary key);
Table created.
SQL> create table child(parentid int);
Table created.
SQL> alter table child add constraint fk_constraint_1 foreign
key(parentid)
2 references parent(id);
Table altered.
SQL> alter table child add constraint fk_constraint_2 foreign
key(parentid)
2 references parent(id);
alter table child add constraint fk_constraint_2 foreign key(parentid)
*
ERROR at line 1:
ORA-02275: such a referential constraint already exists in the table
SQL>=20
SQL>=20
SQL> drop table child;
Table dropped.
SQL> create table child
2 (parentid int,
3 constraint fk_constraint_1 foreign key(parentid) references
parent(id),
4 constraint fk_constraint_2 foreign key(parentid) references
parent(id));
Table created.
I wanted to share this with you, so be aware of this behavior.
-----------------------
Regis Biassala (DBA)
Direct: +353 1 8063613
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