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mysqli::set_charset

mysqli_set_charset

(PHP 5 >= 5.0.5, PHP 7)

mysqli::set_charset -- mysqli_set_charsetクライアントのデフォルト文字セットを設定する

説明

オブジェクト指向型

bool mysqli::set_charset ( string $charset )

手続き型

bool mysqli_set_charset ( mysqli $link , string $charset )

データベースサーバーとのデータの送受信に使用する、 デフォルトの文字セットを設定します。

パラメータ

link

手続き型のみ: mysqli_connect() あるいは mysqli_init() が返すリンク ID。

charset

デフォルトとして設定する文字セット。

返り値

成功した場合に TRUE を、失敗した場合に FALSE を返します。

注意

注意:

Windows プラットフォームでこの関数を使用するには、MySQL クライアント ライブラリのバージョン 4.1.11 以降(MySQL 5.0 の場合は 5.0.6 以降) が必要です。

注意:

文字セットを変更するにはこの方法を使うことを推奨します。 mysqli_query() で (SET NAMES utf8 などとして) 設定する方法はお勧めできません。詳細は MySQL の文字セットの概念 を参照ください。

例1 mysqli::set_charset() の例

オブジェクト指向型

<?php
$mysqli 
= new mysqli("localhost""my_user""my_password""test");

/* 接続状況をチェックします */
if (mysqli_connect_errno()) {
    
printf("Connect failed: %s\n"mysqli_connect_error());
    exit();
}

printf("Initial character set: %s\n"$mysqli->character_set_name());

/* 文字セットを utf8 に変更します */
if (!$mysqli->set_charset("utf8")) {
    
printf("Error loading character set utf8: %s\n"$mysqli->error);
    exit();
} else {
    
printf("Current character set: %s\n"$mysqli->character_set_name());
}

$mysqli->close();
?>

手続き型

<?php
$link 
mysqli_connect('localhost''my_user''my_password''test');

/* 接続状況をチェックします */
if (mysqli_connect_errno()) {
    
printf("Connect failed: %s\n"mysqli_connect_error());
    exit();
}

printf("Initial character set: %s\n"mysqli_character_set_name($link));

/* 文字セットを utf8 に変更します */
if (!mysqli_set_charset($link"utf8")) {
    
printf("Error loading character set utf8: %s\n"mysqli_error($link));
    exit();
} else {
    
printf("Current character set: %s\n"mysqli_character_set_name($link));
}

mysqli_close($link);
?>

上の例の出力は、 たとえば以下のようになります。

Initial character set: latin1
Current character set: utf8

参考

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User Contributed Notes 6 notes

up
5
Konstantin Rozinov
5 months ago
The comment by Claude (http://php.net/manual/en/mysqli.set-charset.php#121067) is CORRECT.

Setting the charset (it's really the encoding) like this after setting up your connection:
$connection->set_charset("utf8mb4")

FAILS to set the proper collation for the connection:

character_set_client: utf8mb4
character_set_connection: utf8mb4
character_set_database: utf8mb4
character_set_filesystem: binary
character_set_results: utf8mb4
character_set_server: utf8mb4
character_set_system: utf8
collation_connection: utf8mb4_general_ci <---- still says general
collation_database: utf8mb4_unicode_ci
collation_server: utf8mb4_unicode_ci

If you use SET NAMES, that works:
$connection->query("SET NAMES utf8mb4 COLLATE utf8mb4_unicode_ci");

character_set_client: utf8mb4
character_set_connection: utf8mb4
character_set_database: utf8mb4
character_set_filesystem: binary
character_set_results: utf8mb4
character_set_server: utf8mb4
character_set_system: utf8
collation_connection: utf8mb4_unicode_ci <-- now says unicode
collation_database: utf8mb4_unicode_ci
collation_server: utf8mb4_unicode_ci

Please note, that I set the following variables on the server:

Set the following to be: utf8mb4_unicode_ci

character_set_client
character_set_connection
character_set_database
character_set_results
character_set_server

collation_connection
collation_server

Set:

character-set-client-handshake = FALSE or 0
skip-character-set-client-handshake = TRUE or 1
up
4
Emmanuel Appiah
1 year ago
So in my case, I had tried changing the collation from utf8mb4_unicode_ci for mysql and had to change it to uft8_general_ci.

Then pasted :

mysqli_set_charset( $con, 'utf8');

right before I did the SELECT command.

This is my code for reading from db :

/*

$DB_SERVER="db_server_name";
$DB_USER_READER="root";
$DB_PASS_READER="passw*rd";
$DB_NAME="db_name";
$DB_PORT="port number";

$SELECT_WHAT="`name_of_column_as_in_your_table`";
$WHICH_TBL="`table_name`";
$ON_WHAT_CONDITION="`id`='7'";

*/

$con = mysqli_connect($DB_SERVER, $DB_USER_READER, $DB_PASS_READER, $DB_NAME, $DB_PORT);//this is the unique connection for the selection
   
    mysqli_set_charset( $con, 'utf8');
   
       
        $slct_stmnt = "SELECT ".$SELECT_WHAT." FROM ".$WHICH_TBL." WHERE ".$ON_WHAT_CONDITION;

    $slct_query = mysqli_query($con, $slct_stmnt);
   
        if ($slct_query==true) {
//Do your stuff here . . .
}

And it worked like a charm. All the best. The above code can work with reading chineese, russian or arabic or any international language from the database's table column holding such data.
up
5
coder at punkass dot com
11 years ago
On windows, with "stock" PHP 5.1.2, there is no set_charset function at all. One may have to replace php_mysqli.dll, and libmysql.dll with proper versions, which provided by MySQL at http://dev.mysql.com/downloads/connector/php/
up
1
claude dot pache at gmail dot com
9 months ago
Although the documentation says that using that function is preferred than using SET NAMES, it is not sufficient in case you use a collation different from the default one:

<?php
// That will reset collation_connection to latin1_swedish_ci
// (the default collation for latin1):
$mysqli->set_charset('latin1');

// You have to execute the following statement *after* mysqli::set_charset()
// in order to get the desired value for collation_connection:
$mysqli->query("SET NAMES latin1 COLLATE latin1_german1_ci");
up
0
chris at ocproducts dot com
1 month ago
Note that using utf8mb4 with this function may cause this function to return false, depending on the MySQL client library compiled into PHP. If the client library is older than the introduction of utf8mb4, then PHP's call of the libraries 'mysql_set_character_set' will return an error because it won't recognise that character set.

The only way you will know there's an error is by checking the return value, because PHP warnings are not emitted by this function.
mysqli_error will return something like:
"Can't initialize character set utf8mb4 (path: /usr/share/mysql/charsets/)"
(I don't think the directory has anything to do with it; I think the utf8mb4 vs utf8 distinction is handled internally)

A workaround is to recall with utf8, then do a 'SET NAMES' query with utf8mb4.

If your MySQL server is configured to use utf8 by default, then you may not notice any of this until you get obscure bugs. It seems it will still save into the database correctly in terms of bytes. However, you may get "Data too long for column" errors if you are truncating strings to fit fields, because from MySQL's point of view during the length check every 4-byte character will actually be multiple individual characters. This caused me hours of debugging.
up
-3
robertoeyzaguirre at hotmail dot com
4 months ago
self::$cont =  new PDO( "mysql:host=".self::$dbHost.";"."dbname=".self::$dbName.";"." charset=utf8", self::$dbUsername, self::$dbUserPassword);
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