MySQL İşlevleri
PHP Manual

mysql_real_escape_string

(PHP 4 >= 4.3.0, PHP 5)

mysql_real_escape_stringEscapes special characters in a string for use in an SQL statement

Uyarı

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:

Açıklama

string mysql_real_escape_string ( string $unescaped_string [, resource $link_identifier = NULL ] )

Escapes special characters in the unescaped_string, taking into account the current character set of the connection so that it is safe to place it in a mysql_query(). If binary data is to be inserted, this function must be used.

mysql_real_escape_string() calls MySQL's library function mysql_real_escape_string, which prepends backslashes to the following characters: \x00, \n, \r, \, ', " and \x1a.

This function must always (with few exceptions) be used to make data safe before sending a query to MySQL.

Dikkat

Security: the default character set

The character set must be set either at the server level, or with the API function mysql_set_charset() for it to affect mysql_real_escape_string(). See the concepts section on character sets for more information.

Değiştirgeler

unescaped_string

The string that is to be escaped.

bağlantı_belirteci

MySQL bağlantısı. Eğer bağlantı belirteci belirtilmemişse mysql_connect() tarafından açılan son bağlantı kullanılmaya çalışılır. Eğer böyle bir bağlantı yoksa mysql_connect() değiştirgesiz olarak çağrılmış gibi bir bağlantı oluşturmaya çalışır. Hiçbir bağlantı yoksa ve yenisi de kurulamazsa E_WARNING seviyesinde bir hata üretilir.

Dönen Değerler

Returns the escaped string, or FALSE on error.

Örnekler

Örnek 1 Simple mysql_real_escape_string() example

<?php
// Connect
$link mysql_connect('mysql_host''mysql_user''mysql_password')
    OR die(
mysql_error());

// Query
$query sprintf("SELECT * FROM users WHERE user='%s' AND password='%s'",
            
mysql_real_escape_string($user),
            
mysql_real_escape_string($password));
?>

Örnek 2 An example SQL Injection Attack

<?php
// We didn't check $_POST['password'], it could be anything the user wanted! For example:
$_POST['username'] = 'aidan';
$_POST['password'] = "' OR ''='";

// Query database to check if there are any matching users
$query "SELECT * FROM users WHERE user='{$_POST['username']}' AND password='{$_POST['password']}'";
mysql_query($query);

// This means the query sent to MySQL would be:
echo $query;
?>

The query sent to MySQL:

SELECT * FROM users WHERE user='aidan' AND password='' OR ''=''

This would allow anyone to log in without a valid password.

Notlar

Bilginize:

A MySQL connection is required before using mysql_real_escape_string() otherwise an error of level E_WARNING is generated, and FALSE is returned. If link_identifier isn't defined, the last MySQL connection is used.

Bilginize:

If magic_quotes_gpc is enabled, first apply stripslashes() to the data. Using this function on data which has already been escaped will escape the data twice.

Bilginize:

If this function is not used to escape data, the query is vulnerable to SQL Injection Attacks.

Bilginize: mysql_real_escape_string() does not escape % and _. These are wildcards in MySQL if combined with LIKE, GRANT, or REVOKE.

Ayrıca Bakınız


MySQL İşlevleri
PHP Manual