Using jQuery's ajax along with a database query multiple times

Question

The problem I am having is understanding how to use the jQuery ajax capabilities to return results for multiple scenarios of a database query.

Here is the code I have so far... this is the ajax function:

function checkDB(code)
{

  $.ajax({
  type: "POST",
  url: "<?php bloginfo('template_url'); ?>/profile/check_code.php",
  data: 'code='+code,
  datatype: "html",
  success: function(result){

       if(result == 0)
       {
        $('#success').html( code + ' already exists.');
       // alert('success');//testing purposes
       }
       else
       {
        $('#err').html(  code + ' isnt in the database!!.');
        //alert('fail');//testing purposes
       }

alert(result);     


      }
  })

}

And this uses the following form to run the function on submit:

   <form method="post" name="sc_ajax" onsubmit="checkDB(document.sc_ajax.sc_voucher_code.value); return false;">
         ...
   </form>

Which runs the database query in check_code.php:

    $code = mysql_real_escape_string($_POST['code']);  

$resultcode = mysql_query('select * from wp_scloyalty where code = "'. $code .'"' ) or die(mysql_error());  
if(mysql_num_rows($resultcode)>0){
    //Exists  
    echo 0;  
}else{  
    //Doesnt Exist
    echo 1;  
}

What I have so far works in that I get a message saying whether the entered code exists in the database.

My question is how would I go about doing more with the query. For example having more "if statements" to test more columns in the database? I want to say "if the code is already in the database, do something different if the 'redeemed' column is set to 1 (default 0)"?

Currently I can only output things based on the function(result) from the ajax reply, but is there a more efficient way to do what Ive done? Or a more efficient way to make the current set up more flexible?

A bit of a long question, sorry, but I feel I need a few things cleared up,

Thanks guys :)

Do you want your PHP code to do more based on the DB result, or the Javascript code to do more? — Paul Grime
– Paul Grime, Commented Feb 16, 2012 at 19:08
Well thats what I am unsure about... I have been lookign around for other peoples approaches on using ajax and I have just decided to use 1 php file to run if statements to return a number, and throw an error or something based on that number. Is this the best/most common approach to work with data from a query using ajax? — JamesG
– JamesG, Commented Feb 16, 2012 at 19:21
I guess it depends what you want your app to do. What you have is a perfectly reasonable attempt at seeing if a code exists. An extension of the PHP could output the column values if it finds the code in the database, for instance. — Paul Grime
– Paul Grime, Commented Feb 16, 2012 at 19:28
For one, you can use this wonderful form plugin. This will autmatically post your form without you having to pick out individual fields. — Juzer Ali
– Juzer Ali, Commented Feb 16, 2012 at 19:36
@PaulGrime yeah thanks for that, ill try it out. @ juzerali, I heard about that jQuery plugin but I wanted to learn more about ajax with jQuery from a lower level so using this simple example is a good start me thinks. Thanks though, ill be using it int the future — JamesG
– JamesG, Commented Feb 16, 2012 at 21:41

Caimen · Accepted Answer · 2012-02-16 20:03:20Z

1

It seems to me what you are really wanting is a way to send the data back to the client in a way javascript can interpret. For that I would recommend sending JSON back to the client using json_encode in PHP.

I would follow these links if you want to learn how to do ajax properly. You are almost there.

http://www.w3schools.com/json/default.asp Learn JSON

Use json_encode on the server side.

http://php.net/manual/en/function.json-encode.php

answered Feb 16, 2012 at 20:03

Caimen

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1 Comment

JamesG Over a year ago

Brilliant mate, thanks. After trying something out its nice to be pointed int eh right direction with something like this :)

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