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From fjoe@iclub.nsu.ru Tue Jan 23 03:38:45 2001
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Tue, 23 Jan 2001 14:31:25 +0600 (NS)
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(envelope-from fjoe@iclub.nsu.ru)
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Date: Tue, 23 Jan 2001 14:31:24 +0600 (NS)
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From: Max Khon <fjoe@iclub.nsu.ru>
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To: Bruce Momjian <pgman@candle.pha.pa.us>
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cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
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Subject: Re: [HACKERS] Bug in FOREIGN KEY
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In-Reply-To: <200101230416.XAA04293@candle.pha.pa.us>
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Message-ID: <Pine.BSF.4.21.0101231429310.12474-100000@iclub.nsu.ru>
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MIME-Version: 1.0
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Content-Type: TEXT/PLAIN; charset=US-ASCII
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Status: RO
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hi, there!
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On Mon, 22 Jan 2001, Bruce Momjian wrote:
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>
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> > This problem with foreign keys has been reported to me, and I have confirmed
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> > the bug exists in current sources. The DELETE should succeed:
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> >
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> > ---------------------------------------------------------------------------
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> >
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> > CREATE TABLE primarytest2 (
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> > col1 INTEGER,
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> > col2 INTEGER,
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> > PRIMARY KEY(col1, col2)
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> > );
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> >
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> > CREATE TABLE foreigntest2 (col3 INTEGER,
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> > col4 INTEGER,
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> > FOREIGN KEY (col3, col4) REFERENCES primarytest2
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> > );
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> > test=> BEGIN;
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> > BEGIN
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> > test=> INSERT INTO primarytest2 VALUES (5,5);
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> > INSERT 27618 1
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> > test=> DELETE FROM primarytest2 WHERE col1 = 5 AND col2 = 5;
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> > ERROR: triggered data change violation on relation "primarytest2"
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I have another (slightly different) example:
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--- cut here ---
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test=> CREATE TABLE pr(obj_id int PRIMARY KEY);
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NOTICE: CREATE TABLE/PRIMARY KEY will create implicit index 'pr_pkey' for
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table 'pr'
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CREATE
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test=> CREATE TABLE fr(obj_id int REFERENCES pr ON DELETE CASCADE);
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NOTICE: CREATE TABLE will create implicit trigger(s) for FOREIGN KEY
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check(s)
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CREATE
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test=> BEGIN;
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BEGIN
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test=> INSERT INTO pr (obj_id) VALUES (1);
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INSERT 200539 1
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test=> INSERT INTO fr (obj_id) SELECT obj_id FROM pr;
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INSERT 200540 1
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test=> DELETE FROM fr;
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ERROR: triggered data change violation on relation "fr"
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test=>
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--- cut here ---
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we are running postgresql 7.1 beta3
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/fjoe
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From sszabo@megazone23.bigpanda.com Tue Jan 23 13:41:55 2001
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Received: from megazone23.bigpanda.com (rfx-64-6-210-138.users.reflexcom.com [64.6.210.138])
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by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id NAA19924
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for <pgman@candle.pha.pa.us>; Tue, 23 Jan 2001 13:41:54 -0500 (EST)
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Received: from localhost (sszabo@localhost)
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by megazone23.bigpanda.com (8.11.1/8.11.1) with ESMTP id f0NIfLa41018;
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Tue, 23 Jan 2001 10:41:21 -0800 (PST)
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Date: Tue, 23 Jan 2001 10:41:21 -0800 (PST)
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From: Stephan Szabo <sszabo@megazone23.bigpanda.com>
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To: Bruce Momjian <pgman@candle.pha.pa.us>
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cc: Jan Wieck <janwieck@Yahoo.com>, Peter Eisentraut <peter_e@gmx.net>,
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PostgreSQL-development <pgsql-hackers@postgresql.org>
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Subject: Re: [HACKERS] Bug in FOREIGN KEY
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In-Reply-To: <200101230417.XAA04332@candle.pha.pa.us>
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Message-ID: <Pine.BSF.4.21.0101231031290.40955-100000@megazone23.bigpanda.com>
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MIME-Version: 1.0
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Content-Type: TEXT/PLAIN; charset=US-ASCII
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Status: RO
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> > Think I misinterpreted the SQL3 specs WR to this detail. The
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> > checks must be made per statement, not at the transaction
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> > level. I'll try to fix it, but we need to define what will
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> > happen with referential actions in the case of conflicting
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> > actions on the same key - there are some possible conflicts:
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> >
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> > 1. DEFERRED ON DELETE NO ACTION or RESTRICT
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> >
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> > Do the referencing rows reference to the new PK row with
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> > the same key now, or is this still a constraint
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> > violation? I would say it's not, because the constraint
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> > condition is satisfied at the end of the transaction. How
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> > do other databases behave?
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> >
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> > 2. DEFERRED ON DELETE CASCADE, SET NULL or SET DEFAULT
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> >
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> > Again I'd say that the action should be suppressed
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> > because a matching PK row is present at transaction end -
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> > it's not the same old row, but the constraint itself is
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> > still satisfied.
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I'm not actually sure on the cascade, set null and set default. The
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way they are written seems to imply to me that it's based on the state
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of the database before/after the command in question as opposed to the
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deferred state of the database because of the stuff about updating the
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state of partially matching rows immediately after the delete/update of
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the row which wouldn't really make sense when deferred. Does anyone know
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what other systems do with a case something like this all in a
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transaction:
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create table a (a int primary key);
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create table b (b int references a match full on update cascade
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on delete cascade deferrable initially deferred);
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insert into a values (1);
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insert into a values (2);
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insert into b values (1);
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delete from a where a=1;
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select * from b;
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commit;
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From pgsql-hackers-owner+M3901@postgresql.org Fri Jan 26 17:00:24 2001
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Received: from mail.postgresql.org (webmail.postgresql.org [216.126.85.28])
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for <pgman@candle.pha.pa.us>; Fri, 26 Jan 2001 17:00:24 -0500 (EST)
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(envelope-from pgsql-hackers-owner+M3901@postgresql.org)
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for <pgsql-hackers@postgresql.org>; Fri, 26 Jan 2001 16:52:48 -0500 (EST)
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(envelope-from janwieck@yahoo.com)
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Received: from j13.us.greatbridge.com (HELO jupiter.greatbridge.com) (216.54.52.153)
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Fri, 26 Jan 2001 17:02:32 -0500
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From: Jan Wieck <janwieck@Yahoo.com>
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Message-Id: <200101262202.RAA04701@jupiter.greatbridge.com>
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Subject: Re: [HACKERS] Bug in FOREIGN KEY
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In-Reply-To: <200101262110.QAA06902@candle.pha.pa.us> from Bruce Momjian at "Jan
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26, 2001 04:10:22 pm"
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To: Bruce Momjian <pgman@candle.pha.pa.us>
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Date: Fri, 26 Jan 2001 17:02:32 -0500 (EST)
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CC: Jan Wieck <janwieck@Yahoo.com>, Peter Eisentraut <peter_e@gmx.net>,
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PostgreSQL-development <pgsql-hackers@postgresql.org>
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X-Mailer: ELM [version 2.4ME+ PL68 (25)]
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MIME-Version: 1.0
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Precedence: bulk
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Sender: pgsql-hackers-owner@postgresql.org
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Status: RO
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Bruce Momjian wrote:
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> Here is another bug:
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>
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> test=> begin;
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> BEGIN
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> test=> INSERT INTO primarytest2 VALUES (5,5);
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> INSERT 18757 1
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> test=> UPDATE primarytest2 SET col2=1 WHERE col1 = 5 AND col2 = 5;
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> ERROR: deferredTriggerGetPreviousEvent: event for tuple (0,10) not
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> found
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Schema?
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Jan
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--
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#======================================================================#
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# It's easier to get forgiveness for being wrong than for being right. #
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# Let's break this rule - forgive me. #
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#================================================== JanWieck@Yahoo.com #
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_________________________________________________________
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Do You Yahoo!?
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Get your free @yahoo.com address at http://mail.yahoo.com
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From pgsql-hackers-owner+M3864@postgresql.org Fri Jan 26 10:07:36 2001
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Received: from mail.postgresql.org (webmail.postgresql.org [216.126.85.28])
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for <pgman@candle.pha.pa.us>; Fri, 26 Jan 2001 10:07:35 -0500 (EST)
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(envelope-from pgsql-hackers-owner+M3864@postgresql.org)
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for <pgsql-hackers@postgresql.org>; Fri, 26 Jan 2001 10:00:34 -0500 (EST)
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(envelope-from peter_e@gmx.net)
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id 14MALp-0006Im-00; Fri, 26 Jan 2001 15:59:45 +0100
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Date: Fri, 26 Jan 2001 16:07:27 +0100 (CET)
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From: Peter Eisentraut <peter_e@gmx.net>
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To: Hiroshi Inoue <Inoue@tpf.co.jp>
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cc: Bruce Momjian <pgman@candle.pha.pa.us>,
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PostgreSQL-development <pgsql-hackers@postgresql.org>
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Subject: Re: [HACKERS] Open 7.1 items
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In-Reply-To: <3A70FA87.933B3D51@tpf.co.jp>
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Message-ID: <Pine.LNX.4.30.0101261604030.769-100000@peter.localdomain>
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MIME-Version: 1.0
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Precedence: bulk
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Sender: pgsql-hackers-owner@postgresql.org
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Status: RO
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Hiroshi Inoue writes:
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> What does this item mean ?
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> Is it the following ?
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>
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> begin;
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> insert into pk (id) values (1);
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> update(delete from) pk where id=1;
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> ERROR: triggered data change violation on relation pk"
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>
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> If so, isn't it a simple bug ?
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Depends on the definition of "bug". It's not spec compliant and it's not
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documented and it's annoying. But it's been like this for a year and the
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issue is well known and can normally be avoided. It looks like a
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documentation to-do to me.
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--
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Peter Eisentraut peter_e@gmx.net http://yi.org/peter-e/
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From pgsql-hackers-owner+M3876@postgresql.org Fri Jan 26 13:07:10 2001
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for <pgsql-hackers@postgreSQL.org>; Fri, 26 Jan 2001 13:03:11 -0500 (EST)
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From: "Mikheev, Vadim" <vmikheev@SECTORBASE.COM>
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To: "'Jan Wieck'" <janwieck@Yahoo.com>,
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PostgreSQL HACKERS
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<pgsql-hackers@postgresql.org>,
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Bruce Momjian <root@candle.pha.pa.us>
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Subject: RE: [HACKERS] Open 7.1 items
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Date: Fri, 26 Jan 2001 10:02:59 -0800
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MIME-Version: 1.0
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Sender: pgsql-hackers-owner@postgresql.org
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Status: RO
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> > FOREIGN KEY INSERT & UPDATE/DELETE in transaction "change violation"
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>
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> A well known issue, and I've asked multiple times how exactly
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> we want to define the behaviour for deferred constraints. Do
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> foreign keys reference just to a key value and are happy with
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> it's existance, or do they refer to a particular row?
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I think first. The last is closer to OODBMS world, not to [O]RDBMS one.
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> Consider you have a deferred "ON DELETE CASCADE" constraint
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> and do a DELETE, INSERT of a PK. Do the FK rows need to be
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> deleted or not?
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Good example. I think FK should not be deleted. If someone really
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want to delete "old" FK then he can do
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DELETE PK;
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SET CONSTRAINT ... IMMEDIATE; -- FK need to be deleted here
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INSERT PK;
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> Consider you have a deferred "ON DELETE RESTRICT" and "ON
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> UPDATE CASCADE" constraint. If you DELETE PK1 and UPDATE PK2
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> to PK1, the FK2 rows need to follow, but does PK2 inherit all
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> FK1 rows now so it's the master of both groups?
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Yes. Again one can use SET CONSTRAINT to achieve desirable results.
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It seems that SET CONSTRAINT was designed for these purposes - ie
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for better flexibility.
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Though, it would be better to look how other DBes handle all these
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cases -:)
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Vadim
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From janwieck@yahoo.com Fri Jan 26 12:20:27 2001
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Received: from smtp6.mail.yahoo.com (smtp6.mail.yahoo.com [128.11.69.103])
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by candle.pha.pa.us (8.9.0/8.9.0) with SMTP id MAA22158
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for <root@candle.pha.pa.us>; Fri, 26 Jan 2001 12:20:27 -0500 (EST)
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Received: from j13.us.greatbridge.com (HELO jupiter.greatbridge.com) (216.54.52.153)
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by smtp.mail.vip.suc.yahoo.com with SMTP; 26 Jan 2001 17:20:26 -0000
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Received: (from janwieck@localhost)
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by jupiter.greatbridge.com (8.9.3/8.9.3) id MAA03196;
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Fri, 26 Jan 2001 12:30:05 -0500
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From: Jan Wieck <janwieck@yahoo.com>
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Message-Id: <200101261730.MAA03196@jupiter.greatbridge.com>
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Subject: Re: [HACKERS] Open 7.1 items
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To: PostgreSQL HACKERS <pgsql-hackers@postgreSQL.org>,
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Bruce Momjian <root@candle.pha.pa.us>
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Date: Fri, 26 Jan 2001 12:30:05 -0500 (EST)
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X-Mailer: ELM [version 2.4ME+ PL68 (25)]
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MIME-Version: 1.0
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Content-Type: text/plain; charset=US-ASCII
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Content-Transfer-Encoding: 7bit
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Status: RO
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Bruce Momjian wrote:
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> Here are my open 7.1 items. Thanks for shrinking the list so far.
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>
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> ---------------------------------------------------------------------------
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>
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> FreeBSD locale bug
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> Reorder INSERT firing in rules
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I don't recall why this is wanted. AFAIK there's no reason
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NOT to do so, except for the actual state of beeing far too
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close to a release candidate.
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> Philip Warner UPDATE crash
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> JDBC LargeObject short read return value missing
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> SELECT cash_out(1) crashes all backends
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> LAZY VACUUM
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> FOREIGN KEY INSERT & UPDATE/DELETE in transaction "change violation"
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A well known issue, and I've asked multiple times how exactly
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we want to define the behaviour for deferred constraints. Do
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foreign keys reference just to a key value and are happy with
|
|
it's existance, or do they refer to a particular row?
|
|
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|
Consider you have a deferred "ON DELETE CASCADE" constraint
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and do a DELETE, INSERT of a PK. Do the FK rows need to be
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deleted or not?
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Consider you have a deferred "ON DELETE RESTRICT" and "ON
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UPDATE CASCADE" constraint. If you DELETE PK1 and UPDATE PK2
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to PK1, the FK2 rows need to follow, but does PK2 inherit all
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FK1 rows now so it's the master of both groups?
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These are only two possible combinations. There are many to
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think of. As said, I've asked before, but noone voted yet.
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Move the item to 7.2 anyway, because changing this behaviour
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would require massive changes in the trigger queue *and* the
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generic RI triggers, which cannot be tested enough any more.
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Jan
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> Usernames limited in length
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> Does pg_dump preserve COMMENTs?
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> Failure of nested cursors in JDBC
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> JDBC setMaxRows() is global variable affecting other objects
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> Does JDBC Makefile need current dir?
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> Fix for pg_dump of bad system tables
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> Steve Howe failure query with rules
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> ODBC/JDBC not disconnecting properly?
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> Magnus Hagander ODBC issues?
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> Merge MySQL/PgSQL translation scripts
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> Fix ipcclean on Linux
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> Merge global and template BKI files?
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>
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>
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> --
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> Bruce Momjian | http://candle.pha.pa.us
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> pgman@candle.pha.pa.us | (610) 853-3000
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> + If your life is a hard drive, | 830 Blythe Avenue
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> + Christ can be your backup. | Drexel Hill, Pennsylvania 19026
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>
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--
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#======================================================================#
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# It's easier to get forgiveness for being wrong than for being right. #
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# Let's break this rule - forgive me. #
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#================================================== JanWieck@Yahoo.com #
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_________________________________________________________
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Do You Yahoo!?
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Get your free @yahoo.com address at http://mail.yahoo.com
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From pgsql-general-owner+M590@postgresql.org Tue Nov 14 16:30:40 2000
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Received: from mail.postgresql.org (webmail.postgresql.org [216.126.85.28])
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Tue, 14 Nov 2000 14:25:51 -0800 (PST)
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Date: Tue, 14 Nov 2000 14:25:51 -0800 (PST)
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From: Stephan Szabo <sszabo@megazone23.bigpanda.com>
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To: "Beth K. Gatewood" <bethg@mbt.washington.edu>
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cc: pgsql-general@postgresql.org
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Subject: Re: [GENERAL] a request for some experienced input.....
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In-Reply-To: <3A11ACA1.E5D847DD@mbt.washington.edu>
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Message-ID: <Pine.BSF.4.21.0011141403380.68986-100000@megazone23.bigpanda.com>
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MIME-Version: 1.0
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Content-Type: TEXT/PLAIN; charset=US-ASCII
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Precedence: bulk
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Sender: pgsql-general-owner@postgresql.org
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Status: OR
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On Tue, 14 Nov 2000, Beth K. Gatewood wrote:
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> >
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>
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> Stephan-
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>
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> Thank you so much for taking the effort to answer this these questions. You
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> help is truly appreciated....
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>
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> I just have a few points for clarification.
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>
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> >
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> > MATCH PARTIAL is a specific match type which describes which rows are
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> > considered matching rows for purposes of meeting or failing the
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> > constraint. (In match partial, a fktable (NULL, 2) would match a pk
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> > table (1,2) as well as a pk table (2,2). It's different from match
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> > full in which case (NULL,2) would be invalid or match unspecified
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> > in which case it would match due to the existance of the NULL in any
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> > case). There are some bizarre implementation details involved with
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> > it and it's different from the others in ways that make it difficult.
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> > It's in my list of things to do, but I haven't come up with an acceptable
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> > mechanism in my head yet.
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>
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> Does this mean, currently that I can not have foreign keys with null values?
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Not exactly...
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Match full = In FK row, all columns must be NULL or the value of each
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column must not be null and there is a row in the PK table where
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each referencing column equals the corresponding referenced
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column.
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Unspecified = In FK row, at least one column must be NULL or each
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referencing column shall be equal to the corresponding referenced
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column in some row of the referenced table
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Match partial is similar to match full except we ignore the null columns
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for purposes of the each referencing column equals bit.
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For example:
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PK Table Key values: (1,2), (1,3), (3,3)
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Attempted FK Table Key values: (1,2), (1,NULL), (5,NULL), (NULL, NULL)
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(hopefully I get this right)...
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In match full, only the 1st and 4th fk values are valid.
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In match partial, the 1st, 2nd, and 4th fk values are valid.
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In match unspecified, all the fk values are valid.
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The other note is that generally speaking, all three are basically the
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same for the single column key. If you're only doing references on one
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column, the match type is mostly meaningless.
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> > PENDANT adds that for each row of the referenced table the values of
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> > the specified column(s) are the same as the values of the specified
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> > column(s) in some row of the referencing tables.
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>
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> I am not sure I know what you mean here.....Are you saying that the value for
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> the FK column must match the value for the PK column?
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I haven't really looked at PENDANT, the above was just a small rewrite of
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some descriptive text in the sql99 draft I have. There's a whole bunch
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of rules in the actual text of the referential constraint definition.
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The base stuff seems to be: (Rf is the referencing columns, T is the
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referenced table)
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3) If PENDANT is specified, then:
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a) For a given row in the referencing table, let pendant
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reference designate an instance in which all Rf are
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non-null.
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b) Let number of pendant paths be the number of pendant
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references to the same referenced row in a referenced table
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from all referencing rows in all base tables.
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c) For every row in T, the number of pendant paths is equal to
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or greater than 1.
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So, I'd read it as every row in T must have at least one referencing row
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in some base table.
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There are some details about updates and that you can't mix PENDANT and
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MATCH PARTIAL or SET DEFAULT actions.
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> > The main issues in 7.0 are that older versions (might be fixed in
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> > 7.0.3) would fail very badly if you used alter table to rename tables that
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> > were referenced in a fk constraint and that you need to give update
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> > permission to the referenced table. For the former, 7.1 will (and 7.0.3
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> > may) give an elog(ERROR) to you rather than crashing the backend and the
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> > latter should be fixed for 7.1 (although you still need to have write
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> > perms to the referencing table for referential actions to work properly)
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>
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> Are the steps to this outlined somewhere then?
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|
The permissions stuff is just a matter of using GRANT and REVOKE to set
|
|
the permissions that a user has to a table.
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