MySQL 函数
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PHP手册

mysql_set_charset

(PHP 5 >= 5.2.3)

mysql_set_charset — Sets the client character set

说明

bool mysql_set_charset ( string $charset [, resource $link_identifier = NULL ] )

Sets the default character set for the current connection.

参数

charset

A valid character set name.

link_identifier

MySQL 连接。如不指定连接标识，则使用由 mysql_connect() 最近打开的连接。如果没有找到该连接，会尝试不带参数调用 mysql_connect() 来创建。如没有找到连接或无法建立连接，则会生成 E_WARNING 级别的错误。

返回值

成功时返回 TRUE， 或者在失败时返回 FALSE.

注释

Note: Suggested alternatives

Use of this extension is discouraged. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API for more information.

Alternatives to this function include:

Note:

This function requires MySQL 5.0.7 or later.

Note:

This is the preferred way to change the charset. Using mysql_query() to execute SET NAMES .. is not recommended.

参见

MySQL 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: Sets the client character set

用户评论:

kraikkonen85 at yahoo dot com (30-Nov-2010 05:39)

Besides setting mysql_set_charset and adding utf8 setting metadata to html, another important but "unpredictable" reason is the encoding type of your PHP editor when saving. For example, if you save the php file other than encodings such as "unicode" or "ANSI", as i experienced, you may notice weird chars like squares, question marks etc.

To make sure, try "save as" method to see explictly that your php file is being saved as utf8.

Hope someone gets help from that, like Ronald stated previously.

Onur

petersealy at aol dot com (07-Apr-2009 05:25)

Having just spent 24 hours banging my head against character sets, explicitly setting all my MySQL databases and tables to utf-8, using mysql_set_charset(), and *still* not solving my character display problems, I'll just remind you that htmlentities() now also takes an optional argument to specify the character set, and that *also* needs to be set to "utf-8" to avoid grief.

humanclock dot com (01-Apr-2009 10:25)

Be careful when working with multiple databases via the same user/host that you specify "true" as the fourth argument to mysql_connect(), otherwise when you call this function it will set both db connections to the same character set.

If you don't pass in "true" to mysql_connect() in the example below, $link1 and $link2 will have the same resource id# and both database connections will end up being set to utf-8 charsets.

<?php
$link1 = mysql_connect('localhost','user1','pass1',TRUE);
$link2 = mysql_connect('localhost','user1','pass1',TRUE);

mysql_selectdb('db1',$link1);
mysql_selectdb('db2',$link2);

mysql_set_charset('latin1',$link1);
mysql_set_charset('utf8',$link2);
?>

Ashus (20-Oct-2008 10:56)

I needed to access the database from within one particular webhosting service. Pages are UTF-8 encoded and data received by forms should be inserted into database without changing the encoding. The database is also in UTF-8.

Neither SET character set 'utf8' or SET names 'utf8' worked properly here, so this workaround made sure all variables are set to utf-8.

<?php

// ... (creating a connection to mysql) ...

mysql_query("SET character_set_results = 'utf8', character_set_client = 'utf8', character_set_connection = 'utf8', character_set_database = 'utf8', character_set_server = 'utf8'", $conn);

$re = mysql_query('SHOW VARIABLES LIKE "%character_set%";')or die(mysql_error());
while ($r = mysql_fetch_assoc($re)) {var_dump ($r); echo "<br />";} exit;

?>

All important variables are now utf-8 and we can safely use INSERTs or SELECTs with mysql_escape_string($var) without any encoding functions.

Ronald (06-Oct-2008 09:33)

I need to revoke most of my post below. What I found out afterwards is this:

1. if you do not use mysql_set_char mysql will NOT do any translations and thus store a utf8-character-byte as is. If you then retrieve this byte from the db and output it in a utf8 page it will show just fine BUT if other apps query this byte (expecting to find a latin1 byte) they will go wrong.

2. the 'bug' mentioned before only occurs if you use a ucase or lcase function in your statement (like: latin1_col = ucase('utf8 string')

Hope this helps, Ronald

Ronald (25-Sep-2008 08:42)

I just hope that the text below will help someone who is struggling with charset encoding, specially when php-charset is different from the mysql-charset. Let me add that I really think that the php man-pages on the mysql-functions are lacking a lot of details on this important issues. Could someone add some useful text here?

Here is my situation. PHP5.2.4, MySql 4.1.15. A php web-application fully utf-8 encoded and a mysql database in latin1 charset.

To make this work I had to:

1. create and store all code files (php, html, inc, js, etc) in the utf-8 charset. Your editor should have an option for this, if not dump it.

2. check that your editor does not add a BOM (http://en.wikipedia.org/wiki/Byte-order_mark) at the beginning of the file. Use a hex-editor to detect them if needed.

3. Set your apache environment to utf-8 by adding 'AddDefaultCharset utf-8' to your .htaccess. If you do not use apache add 'default_charset utf-8' to your php.ini. You have to do either of them (not both), php will use the apache setting where needed.

4. Additionally add this meta-tag to your html-header: '<meta http-equiv="Content-type" content="text/html; charset=UTF-8" />'. This will help silly browsers (Oeps, IE again?) that ignore the utf-response-header send to them.

5. Check that the above line are listened to by check the 'page info' of your pages in firefox. It should show 2 (!!) utf-8 entries.

======== all of the above sofar has nothing to do with mysql ;-) ======

6. Do *NOT* (repeat NOT!) set the 'names' (set names *) or _ANY_ 'character set' (set character set *) (opposed to what they tell you on these pages).

7. Check the previous item by listing the results of the mysql query 'SHOW session VARIABLES'. All char_sets here should say 'latin1', except for the system one which is always 'utf8'. All collations should say 'latin1_*'. Furthermore the php function mysql_client_encoding() should also return latin1 (though I don't understand why; what does this value mean, I would think if php (being the client) is utf8 encoded this would be utf8?)

8 Finally test the above by storing this string in your db and output it in your webpage: 'I?t?rn?ti?nàliz?ti?n and €'.

Now what was interesting during testing and debugging of the above findings was:
1. If I would run 'mysql_set_charset('utf8')' _OR_ 'mysql_query("SET NAMES 'utf8'");' and then run a query in which I would have 'where char_column = 'abc''it would die with 'Illegal mix of collations'

2. If I would run 'mysql_query("SET character_set_client = 'utf8';"); mysql_query("SET character_set_result = 'utf8';")' the query would work BUT the non-ascii-characters would show scrambled in the browser.

3. BUT these 2 points above work just fine on my local dev-machine (php 5.2.3 & mysql 5.0.45)!!!!!!!!

This draws me to these 3 conclusions:

1. The Php-mysql-function library (5.2.+) does a fine job translating utf-8 queries & results to/from latin1! It's better to let php handle this for you then to have mysql do this.

2. Mysql (4.0.+) has 1 or more bugs (well, let's say unfinished features) that involve the charset-translations that are solved in 5.0.+.

3. It is not well enough documented! (Otherwise I would have to write this)

One last remark: clearly characters that exist in utf8 and not in latin1 (and vv.) will get lost during utf8-latin1-utf8 translation.

If any of the above is not correct or not complete feel free to correct this! (Or better yet, add a chapter to the php manual :-)

Cheers, Ronald

nabeelmoidu at gmail dot com (09-Jun-2008 06:11)

Here's an example of how to use this feature :

I'm using  PHP 5.2.5 from http://oss.oracle.com/projects/php/

I wanted to store arabic characters as UTF8 in the database and as suggested in many of the google results, I tried using

mysql_query("SET NAMES 'utf8'");

and

mysql_query("SET CHARACTER SET utf8 ");

but it did not work.

Using the following, it worked flawlessly

$link = mysql_connect('localhost', 'user', 'password');
mysql_set_charset('utf8',$link);

Once this is set we need not manually encode the text into utf using utf8_encode() or other functions. The arabic ( or any UTF8 supported ) text can be passed directly to the database and it is automatically converted by PHP.
For eg.
<?php
$link = mysql_connect('localhost', 'user', 'password');
mysql_set_charset('utf8',$link);
$db_selected = mysql_select_db('emp_feedback', $link);
if (!$db_selected) { die ('Database access error : ' . mysql_error());}
$query = "INSERT INTO feedback ( EmpName, Message ) VALUES ('$_empName','$_message')";
mysql_query($query) or die('Error, Feedback insert into database failed');
?>
Note that here $_empName is stored in English while $_message is in Arabic.

vljubovic AT smartnet DOT ba (04-Mar-2008 08:22)

Using the function provided by Janez and nag worked fine for SELECTs, but with INSERT and UPDATE the non-ascii characters got converted into question marks. To fix this, I replaced SET CHARACTER SET with SET NAMES (ref: http://dev.mysql.com/doc/refman/5.0/en/charset-connection.html). So the function becomes:

<?php
 if (function_exists('mysql_set_charset') === false) {
     /**
      * Sets the client character set.
      *
      * Note: This function requires MySQL 5.0.7 or later.
      *
      * @see http://www.php.net/mysql-set-charset
      * @param string $charset A valid character set name
      * @param resource $link_identifier The MySQL connection
      * @return TRUE on success or FALSE on failure
      */
     function mysql_set_charset($charset, $link_identifier = null)
     {
         if ($link_identifier == null) {
             return mysql_query('SET NAMES "'.$charset.'"');
         } else {
             return mysql_query('SET NAMES "'.$charset.'"', $link_identifier);
         }
     }
 }
 ?>

Anonymous (10-Feb-2008 05:03)

Actually, this function is available in client libraries in MySQL 4.1.13 and newer, too.  So the real version requirement is MySQL >= 5.0.7 OR, if you're using MySQL 4, then >= 4.1.13.

nag QWE svgfr RTY org (17-Dec-2007 03:47)

Here's an improved version of Janez R.'s function:
<?php
if (function_exists('mysql_set_charset') === false) {
    /**
     * Sets the client character set.
     *
     * Note: This function requires MySQL 5.0.7 or later.
     *
     * @see http://www.php.net/mysql-set-charset
     * @param string $charset A valid character set name
     * @param resource $link_identifier The MySQL connection
     * @return TRUE on success or FALSE on failure
     */
    function mysql_set_charset($charset, $link_identifier = null)
    {
        if ($link_identifier == null) {
            return mysql_query('SET CHARACTER SET "'.$charset.'"');
        } else {
            return mysql_query('SET CHARACTER SET "'.$charset.'"', $link_identifier);
        }
    }
}
?>

Janez R. (04-Sep-2007 09:23)

I assume that this is an equivalent in previous versions of php (add some parameter validation and default values though!):
<?
if (!function_exists('mysql_set_charset')) {
  function mysql_set_charset($charset,$dbh)
  {
    return mysql_query("set names $charset",$dbh);
  }
}
?>