Posting and checking if values allready exists in database PHP

Question

So i am posting some strings to my database. I want it to be able to check if it allready exist an id in my database with same name as the new one. In that case it should alert "notvalid". I have also experienced that in some cases it doesn't save the strings at all even though the id is different from the others. Don't know why that happens..

Here is my code

        $.ajax({
                 type : "POST",
                 url : "saveid.php",
                 data:  {"qid": id, "qtext1": text1, "qtext2": text2, "qtext3": text3, "allCounters": allCounters},
                 dataType: "json",
                 success: function(msg2){ 
                    if (msg2 = 'notvalid') {

                    alert(msg2);
                }
                if (msg2 = 'valid') {

                    alert(msg2);    
                }
             }
        });

<?php   
if (isset($_POST['qid']) && isset($_POST['qtext1']) && isset($_POST['qtext2']) && isset($_POST['qtext3']) && isset($_POST['allCounters'])) { 
    $connection = @mysql_connect('localhost', 'root', '') 
        or die (mysql_error()); 
    mysql_select_db('test', $connection) 
        or die (mysql_error()); 

    $id=$_POST['qid'];
    $text1=$_POST['qtext1'];
    $text2=$_POST['qtext2'];
    $text3=$_POST['qtext3'];
    $allCounters=$_POST['allCounters'];

    $result = mysql_query("SELECT * FROM code WHERE id ='$id' LIMIT 1");
    if (mysql_fetch_row($result)) {
        echo json_encode('notvalid');
    } else {
        $query = mysql_query("INSERT INTO code (id, text1, text2, text3, allCounters) VALUES ('$id','$text1','$text2','$text3','$allCounters')"); 
        echo json_encode('valid');
    }


} 
?>

This is the first time i am working with PHP. I will appreciate if someone could explain why this doesn't work, how to make it work or any other tips. Thanks

That was just a clue/example. You need to figure out the rest. There are many many examples on the web that will help you achieve this. Yet that's the usual syntax which is what I use, and works rather well. — Funk Forty Niner
– Funk Forty Niner, Commented Oct 21, 2013 at 16:53
@Koiski Actually you'll be best to use MySQLi_ instead of MySQL_ my version won't work otherwise. FYI: MySQL_ is deprecated. So try if (mysql_num_rows($result)>0) - and change if (msg2 = 'notvalid') to if (msg2 == 'notvalid') and if (msg2 = 'valid') to if (msg2 == 'valid') — Funk Forty Niner
– Funk Forty Niner, Commented Oct 21, 2013 at 17:00
@Koiski Or if (!mysqli_query($connection,$result)) { // rest of your code — Funk Forty Niner
– Funk Forty Niner, Commented Oct 21, 2013 at 17:24

Justin John · Accepted Answer · 2013-10-21 17:02:34Z

1

Please check your code once again.

You are assigning the value, not checking the equality in ajax success callback. So both statements will be true with your code and both alerts will trigger.

Change from

if (msg2 = 'notvalid') {            
         ^

to

if (msg2 == 'notvalid') {
         ^^

Same applies for if (msg2 = 'valid') too.

edited Oct 21, 2013 at 17:02

answered Oct 21, 2013 at 16:57

Justin John

9,74814 gold badges73 silver badges131 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

phil-lavin · Accepted Answer · 2013-10-21 16:51:19Z

1

In answer to your question, see the mysql_num_rows function.

if (mysql_num_rows($result)) {
    echo json_encode('notvalid');
}

As an aside, also look into not using mysql_* functions as they've been deprecated and their use is discouraged. Mysqli and PDO are PHP native alternatives.

If you're using mysql_ functions, you'll need to make sure you escape values going into your database with mysql_real_escape_string() to prevent SQL injection. See http://en.wikipedia.org/wiki/SQL_injection for info.

answered Oct 21, 2013 at 16:51

phil-lavin

1,2278 silver badges19 bronze badges

Collectives™ on Stack Overflow

Posting and checking if values allready exists in database PHP

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related