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				udf_charsets.c
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This is the README file for the udf_charsets.c utility.

The file udf_charsets.c defines user definable functions for MySQL
database server for charset conversions, namely il1_to_ascii,
il2_to_ascii and cp1250_to_ascii, cp1250_to_il2 and il2_to_cp1250.
The *_to_ascii versions strip diacritics from input strings, the other
two provide conversions for two character sets, ISO-8859-2 and
Windows-1250.

The SQL command would be

	select id, name from people where il2_to_ascii(name) = 'jezek';

You might even add function lower, to allow case insensitive search:

		where lower(il2_to_ascii(name)) = 'jezek';

Or do like search:

		where lower(il2_to_ascii(name)) like 'jezek%';

You cannot make index of function, so if you want fast lookup, you
need to have separate column that will hold *_to_ascii'ed values of
the data. Then you put index on this column. Of course, you have to
update this information with each update, which might or might not be
a problem -- MySQL doesn't have triggers, so the change of this
secondary information is up to you.

The conversion sinformation was generated using a Cz::Cstocs Perl
module. The included stript make_il_to_ascii makes it possible to
create function for other charsets. The module Cz::Cstocs is
available from any good CPAN site.

Installation:
	To install this library, you have to compile it into *.so file,
	install it into directory where MySQL will find it, then tell
	MySQL about the functions. For me, this compile command works:

	gcc -Iinclude -shared -o udf_charsets.so udf_charsets.c

	if I'm in the top directory of the mysql-* distribution --
	change the -I option to point to directory that contains the
	mysql.h header file appropriately. If you do not want the
	cp1250 charset, use a -DNOWINSET switch to compiler.

	I then do

	cp udf_charsets.so /usr/lib

	and in the mysql issue SQL command

	create function il2_to_ascii returns string soname "udf_charsets.so";

	Then,

	select il2_to_ascii(name) from table;

	should work. Since you cannot specify full path of the *.so
	file in the create function command, you have to put it to
	some widely recognized directory, probably as a root.

	You have to repeat the create function command for each function
	you want to use in your server.

Problems and bug reports:
	If you find a bug in the code, feel free to mail me. Please,
	always include a version of the library and use meaningful
	Subject line.

Available:
	http://www.fi.muni.cz/~adelton/l10n/

Copyright: (c) 1998--2001 Jan Pazdziora, adelton@fi.muni.cz. All rights
	reserved. This package is free software; you can redistribute
	it and/or modify it under the terms of either GPL or Artistic
	Licence, whichever you like more.