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Re: Help with DELETE statement via ODBC

From: Carlos Abalde <carlos(at)lfcia(dot)org>
To: pgsql-odbc(at)postgresql(dot)org
Cc: Håkon Clausen <hakonhc(at)nospam(dot)hclausen(dot)net>
Subject: Re: Help with DELETE statement via ODBC
Date: 2004-06-07 20:13:41
Message-ID: 20040607201341.GA5962@lfcia.org (view raw or flat)
Thread:
Lists: pgsql-odbc
Håkon Clausen wrote...

> Hi Carlos,
> 
> This is the correct behavior. Deleting 0 rows will give an ODBC error.
> You will have to rewrite your query so that this does not occur.

Hi Håkon,

I'm not an expert on ODBC and maybe this is and philosophical
discussion, buy I think that DELETE querys are very usual in
DB applications, and querys like,

	DELETE FROM table WHERE field = foreign_key

that are very common when you are working with 1-N relations,
need a normal behaviour when 0 rows are deleted.

For example,

	+---------+ 1            N +-----------+
	| Formula |----------------| Parameter |
	+---------+                +-----------+
	for_key			   par_key
	for_txt			   par_for (foreign key)
	...			   par_nam
				   par_val
				   ...

Represents a formula with several parameters. If we have a
new list of parameters for a existing formula, the best way to update
then is to delete the old parameters and create the new ones.
With the current DELETE behaviour, the normal case of a
formula without parameters must be considered as a special
case!

I think that there is a lot of examples like this in DB aplications.
Moreover, as DBs are highly related with Set Theory, it's an error the
current behaviour, because the empty set is dealed as a special case.

These are the mains reasons I think the current behaviour is erroneus.
However, as I said before, maybe this is a philosophical discussion :).

Best regards,


+---.---.---.---.---.---.---.---.---+---.---.---.---.---.---.---.---+
| Carlos Abalde (carlos(at)lfcia(dot)org)  | http://www.lfcia.org/~carlos  |
+ LFCIA Lab, Dept. Computer Science | +34.981.167000 ext. 1275      +
| University of A Coruna, Spain     | PGP Key ID = 0x04DF0EAF       |
+-.---.---.---.---.---.---.---.---.-+-.---.---.---.---.---.---.---.-+

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Subject: Re: Help with DELETE statement via ODBC
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