mysqli::real_escape_string

mysqli_real_escape_string

(PHP 5)

mysqli::real_escape_string -- mysqli_real_escape_string — Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection

说明

面向对象风格

string mysqli::escape_string ( string $escapestr )

string mysqli::real_escape_string ( string $escapestr )

过程化风格

string mysqli_real_escape_string ( mysqli $link , string $escapestr )

This function is used to create a legal SQL string that you can use in an SQL statement. The given string is encoded to an escaped SQL string, taking into account the current character set of the connection.

参数

link

仅以过程化样式：由 mysqli_connect() 或 mysqli_init() 返回的链接标识。

escapestr

The string to be escaped.

Characters encoded are NUL (ASCII 0), \n, \r, \, ', ", and Control-Z.

返回值

Returns an escaped string.

范例

Example #1 mysqli::real_escape_string() example

面向对象风格


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

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

$mysqli->query("CREATE TEMPORARY TABLE myCity LIKE City");

$city = "'s Hertogenbosch";

/* this query will fail, cause we didn't escape $city */
if (!$mysqli->query("INSERT into myCity (Name) VALUES ('$city')")) {
    printf("Error: %s\n", $mysqli->sqlstate);
}

$city = $mysqli->real_escape_string($city);

/* this query with escaped $city will work */
if ($mysqli->query("INSERT into myCity (Name) VALUES ('$city')")) {
    printf("%d Row inserted.\n", $mysqli->affected_rows);
}

$mysqli->close();
?>

过程化风格


<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

mysqli_query($link, "CREATE TEMPORARY TABLE myCity LIKE City");

$city = "'s Hertogenbosch";

/* this query will fail, cause we didn't escape $city */
if (!mysqli_query($link, "INSERT into myCity (Name) VALUES ('$city')")) {
    printf("Error: %s\n", mysqli_sqlstate($link));
}

$city = mysqli_real_escape_string($link, $city);

/* this query with escaped $city will work */
if (mysqli_query($link, "INSERT into myCity (Name) VALUES ('$city')")) {
    printf("%d Row inserted.\n", mysqli_affected_rows($link));
}

mysqli_close($link);
?>

以上例程会输出：

Error: 42000
1 Row inserted.

注释

Note:
For those accustomed to using mysql_real_escape_string(), note that the arguments of mysqli_real_escape_string() differ from what mysql_real_escape_string() expects. The link identifier comes first in mysqli_real_escape_string(), whereas the string to be escaped comes first in mysql_real_escape_string().

参见

mysqli_character_set_name() - Returns the default character set for the database connection

PHP手册 - N: Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection

用户评论:

dave at mausner.us (25-Feb-2011 03:48)

You can avoid all character escaping issues (on the PHP side) if you use prepare() and bind_param(), as an alternative to placing arbitrary string values in SQL statements. This works because bound parameter values are NOT passed via the SQL statement syntax.

Josef Toman (26-Feb-2010 02:14)

For percent sign and underscore I use this: <?php $more_escaped = addcslashes($escaped, '%_'); ?>

vita dot plachy at seznam dot cz (09-Nov-2007 07:37)

The above can be managed by the following function: <?php function search_escape($str, $char = '\\') { return ereg_replace('[%_]', $char . '\0', $str); } ?>

tobias_demuth at web dot de (10-Nov-2005 04:54)

Note, that if no connection is open, mysqli_real_escape_string() will return an empty string!

arnoud at procurios dot nl (07-Oct-2004 05:05)

Note that this function will NOT escape _ (underscore) and % (percent) signs, which have special meanings in LIKE clauses. As far as I know there is no function to do this, so you have to escape them yourself by adding a backslash in front of them.