Re: LIKE wildcards escaping problem

From: Andrew Dunstan <andrew(at)dunslane(dot)net>
To: Thea <monika(dot)morawiecka(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: LIKE wildcards escaping problem
Date: 2007-09-24 12:41:18
Message-ID: 46F7B06E.1070907@dunslane.net
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This is the wrong list to ask this question. This list is about
development, not usage. Please ask on -general in future.

I presume that where you have "/" you really mean "\".

What version of postgres are you using? If you use a modern version with
standard_conforming_strings on then you do not need to escape backslashes.

cheers

andrew

Thea wrote:
> Hello folks :)
>
> I am working on a system that is possible to configure to work with
> several DBMSes, including PG.
>
> My problem is that PG behaves differently than other supported DBMSes
> (MSSQL and MySQL) - when I'm passing a query containing LIKE phrase to
> it, a double amount of '/' literals is needed to obtain expected
> result. I do realize that this is caused by a parser 'collapsing'
> double '/' to a single one.
> I might not express this clearly, but - as I understand it - in
> general result is that to find '/' literal in DB, '////' phrase is
> needed ('////' is turned to '//' by a parser, and that is valid
> expression for '/' literal in SQL itself).
>
> The problem is that I cannot really use ESCAPE clause - it would
> require working on too many files. (there are about 6k files in this
> project, changing most of them would be not only not feasible, but
> also risky)
> The problem is that there is a table with user names. Those can
> contain '/' literal (if they are domain users for example.) And here I
> hit the wall. Any search for username with '/' literal fails.
> I've searched through postgres mailing lists and all feed I could
> google out, and found some info about problem itself, but I was unable
> to find a solution for it anywhere.
>
> Problem was addressed in following locations:
> http://svr5.postgresql.org/pgsql-general/1999-07/msg00340.php
> http://svr5.postgresql.org/pgsql-sql/1999-03/msg00144.php
>
> But those posts are from 1999, and I did not find anything more up-to-
> date.
> Has anyone solved this problem?
> Is there any configuration option in PG allowing to make it behave in
> a more compliant way?
>
> I'd be more than happy to see something like Herouth Maoz suggested
> in
> http://svr5.postgresql.org/pgsql-general/1999-07/msg00340.php , namely
> configuration option for PG, but I was unable to find it.
>
> Sorry if I messed something up... I'm really very confused with this
> sftuff...
> I will appreciate any help or explanation, if I missed something
> important.
>
>
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