[SOLVED] Check before inserting in DB ???

[salman_ahad@yahoo.com]

This is my code

---------------

if ( $_POST ['Submit'])

{{

$username = $_POST ['usernm'];

$userpassword = $_POST ['userpw'];

}

/*insert data from the form into the db table*/

 

$querypost = mysql_query ("INSERT INTO users (usernm, userpw) VALUES ('$username','$userpassword')");

}

?>

 

How do I check before inserting whether that username and password is already inserted. I have an id assigned to every entry.

 

 

[dreamwest]

You can set the fields as UNIQUE, but that will crash your script if you try to add a duplicate, heres an easy way:

 

 if ( $_POST ['Submit']){

$username = mysql_real_escape_string($_POST ['usernm']);
$userpassword = mysql_real_escape_string($_POST ['userpw']);

$result = mysql_query("SELECT usernm FROM users WHERE usernm='{$username}' and  userpw='{$userpassword}'  ");
if($result){

$num = mysql_num_rows( $result );

if ($num == 0) { 
   $querypost = mysql_query ("INSERT INTO users (usernm, userpw) VALUES ('$username','$userpassword')");
}
}
}

[PFMaBiSmAd]

that will crash your script

 

Not if your code contains proper error checking logic.

[salman_ahad@yahoo.com]

 

Thanks. I made a little change and it worked.

 

if ( $_POST ['Submit'])

{

$username = mysql_real_escape_string($_POST ['usernm']);

$userpassword = mysql_real_escape_string($_POST ['userpw']);

$error= "Error while inserting, either User present or other. Please check database";

$inserted= "User inserted";

$result = mysql_query("SELECT usernm FROM users WHERE usernm='{$username}' and  userpw='{$userpassword}'  ");

if($result)

{

$num = mysql_num_rows( $result );

if ($num == 0) {

  $querypost = mysql_query ("INSERT INTO users (usernm, userpw) VALUES ('$username','$userpassword')");

echo $inserted;

}

else echo $error;

}

}

?>