OK
the error was at the db's collation.
thought that i had set default utf8_general_ci collation.
if anyone else has done same mistake here's the script that PRODUCES the sql queries required to change the database's encoding and collation . run it and then paste the produced queries in a phpmyadmin sql script window. ;)
////////////////////////////////////
//////////SCRIPT
/////////////////////////////////////
<?php
// Original script (v1.0) by/from: http://www.phpwact.org/php/i18n/utf-8/mysql
// Improved/modified (v1.05) by Bogdan http://bogdan.org.ua/
// Last updated: 2010-06-28
// this script will output all queries needed to change all fields/tables to a different collation
// it is HIGHLY suggested you make a MySQL backup prior to running any of the generated queries
// this code is provided AS IS and without any warranty
// add text/plain header when used not as a CLI script; PHP CLI SAPI shouldn't output headers
header("Content-Type: text/plain");
// precaution
set_time_limit(0);
// collation you want to change to:
$convert_to = 'utf8_general_ci';
// character set of new collation:
$character_set= 'utf8';
// DB login information - *modify before use*
$username = 'evroglos_moodle2';
$password = 'lF.o$hzw8P](';
$database = 'evroglos_moodle2';
$host = 'localhost';
//-- usually, there is nothing to modify below this line --//
// show TABLE alteration queries?
$show_alter_table = true;
// show FIELD alteration queries?
$show_alter_field = true;
mysql_connect($host, $username, $password);
mysql_select_db($database);
$rs_tables = mysql_query(" SHOW TABLES ") or die(mysql_error());
while ($row_tables = mysql_fetch_row($rs_tables)) {
$table = mysql_real_escape_string($row_tables[0]);
// Alter table collation
// ALTER TABLE `account` DEFAULT CHARACTER SET utf8
if ($show_alter_table)
echo("ALTER TABLE `$table` DEFAULT CHARACTER SET $character_set;\n");
$rs = mysql_query(" SHOW FULL FIELDS FROM `$table` ") or die(mysql_error());
while ( $row = mysql_fetch_assoc($rs) ) {
if ( $row['Collation'] == '' || $row['Collation'] == $convert_to )
continue;
// Is the field allowed to be null?
if ( $row['Null'] == 'YES' )
$nullable = ' NULL ';
else
$nullable = ' NOT NULL ';
// Does the field default to null, a string, or nothing?
if ( $row['Default'] === NULL && $row['Null'] == 'YES' )
$default = " DEFAULT NULL ";
elseif ( $row['Default'] != '' )
$default = " DEFAULT '".mysql_real_escape_string($row['Default'])."'";
else
$default = '';
// sanity check and fix:
if ($nullable == ' NOT NULL ' && $default == ' DEFAULT NULL ') {
$default = '';
echo "/* Warning: wrong combination of 'default value' and 'NULL-flag' detected - and fixed! */\n";
echo "/* Diagnostics: row[Null] = '$row[Null]', row[Default] = " . mysql_real_escape_string($row['Default']) . ", MySQL version: " . mysql_get_server_info() . " */\n";
}
// Don't alter INT columns: no collations, and altering them drops autoincrement values
if (strpos($row['Type'], 'int') !== false) {
$show_alter_field = False;
}
else {
$show_alter_field = True;
}
// Alter field collation:
// ALTER TABLE `tab` CHANGE `field` `field` CHAR( 5 ) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL
if ($show_alter_field) {
$field = mysql_real_escape_string($row['Field']);
echo "ALTER TABLE `$table` CHANGE `$field` `$field` $row[Type] CHARACTER SET $character_set COLLATE $convert_to $nullable $default;\n";
}
}
}
?>
//////////////////////////////////////////
//////////////END OF SCRIPT
/////////////////////////
