Обсуждение: Search

Greetings,

I store  text data  in  windows-1251 encoding in my pgSQL database
and when I execute SQL command like

SELECT title, firstname, lastname, description FROM stuff
 WHERE title LIKE '%<keyword>%' AND firtsname LIKE '%<keyword>%'
 AND lastname LIKE '%<keyword>%' AND description LIKE '%<keyword>%'

the response  comes  really quick,  but if I want case independent
search, I should convert,  using my own PHP3 function, both search
field  and  keyword to low case  just becouse PostgreSQL by itself
doesn't  know how to convert characters  in windows-1251  encoding
to low case. And response time grows from 0:07 to 1:10!

Is there  any  solution?  May be  stored procedures  (that doesn't
require to recompile pgSQL)? Thank you in advance!!!

P.S.:  as far as I know there is no locale for  windows-1251  and,
 unfortunately,  I can't store data in koi8-r whose locale present
 in almost all UNIX'es.

Mentioned above function:
 function lower($str)
 {
  $length = strlen($str);

  for ($i = 0; $i < $length; ++$i)
  {
   $sym = ord($str[$i]);
   if (($sym > 34 && $sym < 60) || ($sym > 191 && $sym < 224))
    $str[$i] = chr($sym + 32);
  }

  return $str;
 }

--
  BEST WISHES, Dmitry
  Webmaster, DeltaCube Studio
  http://www.deltacube.com/

Hi,

For case insensitive you must use the regexp search as follow :

SELECT title, firstname, lastname, description FROM stuff
 WHERE title *~ '.*<keyword>.*' AND firtsname *~ '.*<keyword>.*';


>
> P.S.:  as far as I know there is no locale for  windows-1251  and,
>  unfortunately,  I can't store data in koi8-r whose locale present
>  in almost all UNIX'es.

I don't know about windows-1251. Perhaps this can't help you. But if
you have japanese in you database, you can proceed a search on it so
why not windows-1251 ?

A+

Gilles

At 03:43 +0300 on 01/08/1999, Gilles Darold wrote:


> I don't know about windows-1251. Perhaps this can't help you. But if
> you have japanese in you database, you can proceed a search on it so
> why not windows-1251 ?

Because the backend has to know that the lowercase for char NNN in this
codepage is MMM. This is different from one locale to the next. If it were
windows-1255 (Hebrew), there would be no lowercase at all for any character
above 224. So of course it's different than Japanese.

There can be two solutions to this problem:

1) Write a function using SPI, install it on the backend, and use
   it for the comparison.

2) Create the new locale, or at least the LC_CTYPE part of the locale,
   on the unix you are using.

Herouth

--
Herouth Maoz, Internet developer.
Open University of Israel - Telem project
http://telem.openu.ac.il/~herutma

On Sat, 31 Jul 1999, Dmitry Popov wrote:
> I store  text data  in  windows-1251 encoding in my pgSQL database
> and when I execute SQL command like
>
> SELECT title, firstname, lastname, description FROM stuff
>  WHERE title LIKE '%<keyword>%' AND firtsname LIKE '%<keyword>%'
>  AND lastname LIKE '%<keyword>%' AND description LIKE '%<keyword>%'
>
> the response  comes  really quick,  but if I want case independent
> search, I should convert,  using my own PHP3 function, both search
> field  and  keyword to low case  just becouse PostgreSQL by itself
> doesn't  know how to convert characters  in windows-1251  encoding
> to low case. And response time grows from 0:07 to 1:10!
>
> Is there  any  solution?  May be  stored procedures  (that doesn't
> require to recompile pgSQL)? Thank you in advance!!!

> P.S.:  as far as I know there is no locale for  windows-1251  and,
>  unfortunately,  I can't store data in koi8-r whose locale present
>  in almost all UNIX'es.

   Incorrect solution: install win1251 locale. Once I saw a reference to
such beast in Russian Apache mailing list. Search through mail archive,
look into Apache-Rus FAQs...

   Correct solution: use koi8-r locale and koi8<=>win1251 on-the-fly
conversion. Postgres starting from 6.5 can do on the fly conversion between
many Cyrillic locales. Look into doc/README.locale.

> --
>   BEST WISHES, Dmitry
>   Webmaster, DeltaCube Studio
>   http://www.deltacube.com/

Oleg.
----
    Oleg Broytmann     http://members.xoom.com/phd2/     phd2@earthling.net
           Programmers don't die, they just GOSUB without RETURN.