From: Michael Fuhr <mike@fuhr.org>
To: ASAKALAL@bouyguestelecom.fr
Cc: pgsql-sql@postgresql.org
Subject: Re: Foreign key
Date: Sun, 27 Mar 2005 00:47:20 -0700
Message-ID: <20050327074720.GB46207@winnie.fuhr.org> (raw)
In-Reply-To: <DB7F9CBEADC6D4118F5600508B442F0308611FA4@bt1sqtbe.bpa.bouyguestelecom.fr>
References: <DB7F9CBEADC6D4118F5600508B442F0308611FA4@bt1sqtbe.bpa.bouyguestelecom.fr>
On Fri, Mar 25, 2005 at 04:31:16PM +0100, ASAKALAL@bouyguestelecom.fr wrote:
>
> When i add table with foreign key in my database, this error return : <
> number of referencing and referenced colums for foreign key disagree>.
Apparently the referencing key (the foreign key specification) has
a different number of columns than the referenced key (the primary
key or other unique key in the referenced table). Here's an example
that illustrates the problem:
CREATE TABLE foo (
pk1 integer NOT NULL,
pk2 integer NOT NULL,
PRIMARY KEY (pk1, pk2) -- 2-column primary key
);
CREATE TABLE bar (
fk integer NOT NULL REFERENCES foo -- 1-column foreign key
);
ERROR: number of referencing and referenced columns for foreign key disagree
In the above example we need a 2-column foreign key:
CREATE TABLE bar (
fk1 integer NOT NULL,
fk2 integer NOT NULL,
FOREIGN KEY (fk1, fk2) REFERENCES foo
);
Here's another example that references a 1-column unique key that
isn't a primary key:
CREATE TABLE foo (
pk1 integer NOT NULL,
pk2 integer NOT NULL,
x integer NOT NULL,
PRIMARY KEY (pk1, pk2),
UNIQUE (x)
);
CREATE TABLE bar (
fk integer NOT NULL REFERENCES foo (x)
);
If these examples don't help, then please post the table definitions
you're working with and explain what you'd like to do.
--
Michael Fuhr
http://www.fuhr.org/~mfuhr/
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To: pgsql-sql@postgresql.org
Cc: mike@fuhr.org, ASAKALAL@bouyguestelecom.fr
Subject: Re: Foreign key
In-Reply-To: <20050327074720.GB46207@winnie.fuhr.org>
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