Solved

Sessions and MySQL

Posted on 2002-03-08
5
210 Views
Last Modified: 2008-03-06
I'm making an online app where the my client wants to save a bunch of data into a database including the actual session id then later they'll use this information for something else they're doing.

In any case, I have one part in my program that I can't seem to figure out why.  Here's a snippet

<?PHP
session_start();

$sessionid = session_id();

$queryresult = mysql_query("SELECT * FROM energybook WHERE session='$sessionid'");
$booknumrows = mysql_num_rows($queryresult);

if($booknumrows == 0)
   print "HEY!, I found a one!.  Let's update the existing record";
else
   Print "Let's insert the record now";
?>

The problem here is, I know I have an existing record in my table but the thing is not finding it.  Ok, I know that if I close my browser and reopen, i'll get another session but all this occurs within the SAME session so I don't believe that's the problem.

I'm stumped.
Thanks,
KABOOM
0
Comment
Question by:KABOOM
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
5 Comments
 
LVL 32

Expert Comment

by:Batalf
ID: 6851017
Why this line:

if($booknumrows == 0)

Shouldn't the number of rows be 1 if you should update?

if($booknumrows == 1)



0
 
LVL 5

Expert Comment

by:andriv
ID: 6851288
Batalf is Correct, you will only get the message if no records are found.



0
 
LVL 5

Accepted Solution

by:
dkjariwala earned 50 total points
ID: 6852382
You don't need to select all the fields by using SELECT * , you can just do like

select ANY_ONE_FIELD_NAME from energybook where session='$sessionid';

This would be more efficient.

Also, make sure that query is executed successfully.

$result = mysql_query("select ANY_ONE_FIELD_NAME from energybook where session='$sessionid') or die('Can not execute query. ' . mysql_error());

if(mysql_num_rows($result)>0)
   print "Record exists !!";

JD
0
 
LVL 40

Expert Comment

by:Richard Quadling
ID: 6864129
You could also use COUNT(*) AS RecordCount, rather than actually getting the entire record set back and then counting the rows.

If you are only ever expecting 0 or 1 record, then OK, but if you COULD get thousands of results, then COUNT(*) SHOULD be faster!

e.g.


<?PHP
session_start();

$sessionid = session_id();

$queryresult = mysql_query("SELECT COUNT(*) AS RecordCount FROM energybook WHERE session='$sessionid'");
if (isset($queryresult))
 {
 $booknumrow = mysql_fetch_array($queryresult);

 if($booknumrow[0] > 1) print "Oh dear! Too many SOMEHOW!";
 else if ($booknumrow[0] == 1) print "HEY!, I found a one!.  Let's update the existing record";
 else Print "Let's insert the record now";
 }
?>


Regards,

Richard Quadling.
0
 
LVL 5

Expert Comment

by:dkjariwala
ID: 6864150
Oops I missed on that ,

My friend Richard is DEFINATELY correct.
Infect I shall say use count(*) only. If you just want to check if record is there or not.

JD
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
embadded search engine in website 4 47
A responsive image gallery using flexbox 6 80
php mail() send emails but the message is lost 4 33
php non-object 7 29
Popularity Can Be Measured Sometimes we deal with questions of popularity, and we need a way to collect opinions from our clients.  This article shows a simple teaching example of how we might elect a favorite color by letting our clients vote for …
Things That Drive Us Nuts Have you noticed the use of the reCaptcha feature at EE and other web sites?  It wants you to read and retype something that looks like this. Insanity!  It's not EE's fault - that's just the way reCaptcha works.  But it i…
The viewer will learn how to dynamically set the form action using jQuery.
This tutorial will teach you the core code needed to finalize the addition of a watermark to your image. The viewer will use a small PHP class to learn and create a watermark.

710 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question