foreign key is from different tables - what to do?

On Wed, 2002-02-20 at 18:23, Cyril Samovskiy wrote:

hi. i'm rookie in postgres, so here is my question:

Therefore your question should have gone to pgsql-novice. (Reply-To set
there.)

i have foreign key consisting of 2 fields (a and b). a is foreign key from
table aaa, b is FK from table bbb. how to create table is that complex
foreign key consisiting of fields from different tables?
thank you

You seem to have two foreign keys, not one. I'm guessing that you
actually have a multi-field primary key, each field of which is a
foreign key to another table:

CREATE TABLE aaa (id INTEGER PRIMARY KEY, ...)
CREATE TABLE bbb (id INTEGER PRIMARY KEY, ...)
CREATE TABLE ccc (a INTEGER REFERENCES aaa(id),
b INTEGER REFERENCES bbb(id),
...,
PRIMARY KEY (a, b))

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Isle of Wight http://www.lfix.co.uk/oliver
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hi. i'm rookie in postgres, so here is my question:

OE> Therefore your question should have gone to pgsql-novice. (Reply-To set
OE> there.)

oh, i'm sorry i didn't know that

i have foreign key consisting of 2 fields (a and b). a is foreign key from
table aaa, b is FK from table bbb. how to create table is that complex
foreign key consisiting of fields from different tables?
thank you

OE> You seem to have two foreign keys, not one. I'm guessing that you
OE> actually have a multi-field primary key, each field of which is a
OE> foreign key to another table:

no my primary key is only one field, another one. actually i found how
to make multi-FK from different tables using ALTER TABLE stuff.
anyway thanks a lot for your support
and sorry again for disturbing you
bye

-------------------
Best regards,
Cyril Samovskiy
cyril_s31@yahoo.com
cyril@somiconline.org

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You have to create 2 foreign keys

alter table YourTable
ALTER TABLE "YourTable" ADD CONSTRAINT "my_a_fk" FOREIGN KEY (a) REFERENCES
aaa(a) MATCH FULL;
ALTER TABLE "YourTable" ADD CONSTRAINT "my_b_fk" FOREIGN KEY (b) REFERENCES
bbb(b) MATCH FULL;

Hope this Helps

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----- Original Message -----
From: "Cyril Samovskiy" <cyril_s31@yahoo.com>
To: "Oliver Elphick" <pgsql-novice@postgresql.org>
Sent: Thursday, February 21, 2002 11:39 AM
Subject: Re: [NOVICE] [HACKERS] foreign key is from different tables - what
to do?

hi. i'm rookie in postgres, so here is my question:

OE> Therefore your question should have gone to pgsql-novice. (Reply-To

set

OE> there.)

oh, i'm sorry i didn't know that

i have foreign key consisting of 2 fields (a and b). a is foreign key

from