php mysql_real_escape_string()函数

mysql教程_real_escape_string() 函数转义 SQL 语句中使用的字符串中的特殊字符。

下列字符受影响：

x00
n
r

'
"
x1a
如果成功，则该函数返回被转义的字符串。如果失败，则返回 false。

语法
mysql_real_escape_string(string,connection)参数 描述
string 必需。规定要转义的字符串。
connection 可选。规定 MySQL 连接。如果未规定，则使用上一个连接。
实例

function opendatabase ($host,$user,$pass) {
try {
if ($db = mysql_connect ($host,$user,$pass)){
return $db;
} else {
throw new exception ("Sorry, could not connect to mysql.");
}
} catch (exception $e) {
echo $e->getmessage ();
}
}

function selectdb ($whichdb, $db){
try {
if (!mysql_select_db ($whichdb,$db)){
throw new exception ("Sorry, database could not be opened.");
}
} catch (exception $e) {
echo $e->getmessage();
}
}
function closedatabase ($db){
mysql_close ($db);
}
$db = opendatabase ("localhost","root","");
selectdb ("mydatabase",$db);
$_POST['user'] = "myname";
$_POST['pass'] = "mypassword";

function validatelogin ($user,$pass){
mysql_real_escape_string ($user);
mysql_real_escape_string ($pass);
$thequery = "SELECT * FROM userlogin WHERE username='$user' AND password='$pass'";
if ($aquery = mysql_query ($thequery)){
if (mysql_num_rows ($aquery) > 0){
return true;
} else {
return false;
}
} else {
echo mysql_error();
}
}

if (validatelogin ($_POST['user'],$_POST['pass'])){
echo "You have successfully logged in.";
} else {
echo "Sorry, you have an incorrect username and/or password.";
}

closedatabase ($db);

?>