diff --git a/doc/TODO.detail/view b/doc/TODO.detail/view deleted file mode 100644 index 2b108b1bc8..0000000000 --- a/doc/TODO.detail/view +++ /dev/null @@ -1,74 +0,0 @@ -From pgsql-general-owner+M10387@postgresql.org Mon Jun 4 22:02:55 2001 -Return-path: -Received: from postgresql.org (webmail.postgresql.org [216.126.85.28]) - by candle.pha.pa.us (8.10.1/8.10.1) with ESMTP id f5522tc28169 - for ; Mon, 4 Jun 2001 22:02:55 -0400 (EDT) -Received: from postgresql.org.org (webmail.postgresql.org [216.126.85.28]) - by postgresql.org (8.11.3/8.11.1) with SMTP id f5520BE14492; - Mon, 4 Jun 2001 22:00:11 -0400 (EDT) - (envelope-from pgsql-general-owner+M10387@postgresql.org) -Received: from sss.pgh.pa.us ([192.204.191.242]) - by postgresql.org (8.11.3/8.11.1) with ESMTP id f551hHE09364 - for ; Mon, 4 Jun 2001 21:43:17 -0400 (EDT) - (envelope-from tgl@sss.pgh.pa.us) -Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) - by sss.pgh.pa.us (8.11.3/8.11.3) with ESMTP id f551gwR09928; - Mon, 4 Jun 2001 21:42:58 -0400 (EDT) -To: Rasmus Resen Amossen -cc: pgsql-general@postgresql.org -Subject: Re: [GENERAL] Re: Updating views -In-Reply-To: <3B1C16EC.8D9FB57B@rhk.dk> -References: <20010605001048.A2133@lorien.net> <3B1C16EC.8D9FB57B@rhk.dk> -Comments: In-reply-to Rasmus Resen Amossen - message dated "Tue, 05 Jun 2001 01:17:00 +0200" -Date: Mon, 04 Jun 2001 21:42:57 -0400 -Message-ID: <9925.991705377@sss.pgh.pa.us> -From: Tom Lane -Precedence: bulk -Sender: pgsql-general-owner@postgresql.org -Status: OR - -Rasmus Resen Amossen writes: -> OK, but I can't see how to make a single rule that allows me to update -> an arbitray set of attributes from an arbitray where-clause. - -The reason the system doesn't do that for you is that it's *hard* to -figure out what to do for an arbitrary where-clause. An automatic rule -has no chance of doing the right thing, because the right thing depends -on what you intend. For example, if your view has - select ... where a>5; -what do you think ought to happen if someone tries to insert a row -with a<5? Is that an error? A no-op? Does the row go in anyway, -you just can't see it in the view? Does the row go into some other -table instead? Is it OK to change the A column at all? It all depends -on the semantics of your database design. So you have to figure out -what you want and write rules that do it. - -The mechanics of the rule are not that painful once you've decided what -the reverse mapping from inserted/updated data to underlying tables -ought to be. One thing that may help is to realize that you don't need -a separate rule for each combination of set of attributes that might be -updated. "new.*" is defined for all columns including the ones that -didn't change, so you can just do something like - - update ... set f1 = new.f1, f2 = new.f2, ... - -without worrying about just which columns the user tried to update. -Likewise, the where clause in the user's query is not yours to worry -about; that condition gets added onto the stuff in your rule. - -> In other words: I want to make the update of 'exview' transparent to -> 'extable'. - -If it's really transparent, one wonders why you bothered with a view -at all. Useful views tend to be nontrivial mappings of the underlying -data, which is why it's nontrivial to figure out what the reverse -mapping ought to be. - - regards, tom lane - ----------------------------(end of broadcast)--------------------------- -TIP 6: Have you searched our list archives? - -http://www.postgresql.org/search.mpl -