How to store multi byte characters in SQL Server database using CodeIgniter

Try to convert your input with iconv() before insert to db :

$input = iconv('','UTF-8',$str);

Handling encoding in Microsoft's SQL Server from PHP can be quite painful. The CharacterSet-option was included with version 1.1 of Microsoft SQL Server Driver for PHP (SQLSRV), so there's an off-chance, you are using an outdated version that does not support setting the ChracterSet, although that is unlikely. Changing char_set to UTF-16 is not an option, as SQLSRV only supports UTF-8.

More likely one of the following applies:

• in your php.ini the option default_charset is not set to UTF-8
• as you probably are working on a Windows machine, your .php-file is not encoded in UTF-8.

If this does not solve the problem, then your input probably contains one ore more characters, which are not valid UTF-8. In this case try converting your (user) input with iconv().

edit: Regarding @Markus comment: CodeIgniter's system/database/drivers/sqlsrv/sqlsrv_driver.php looks like a simple wrapper around the sqlsrv-commands, it seems therefore unlikely, that the problem is caused by CodeIgniter-code.