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mysqli transactions not working in php

Posted on 2014-07-31
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799 Views
Last Modified: 2014-08-04
Hi,
I'm having problems getting procedural mysqli transactions to work.    Should I have a mysqli_begin_transaction($dbci) statement?

I'm trying to run each query and if one fails roll back, else commit at the end.

Any pointers gratefully received.

mysqli_autocommit($dbci, FALSE);

	// Make query
$query3 = "INSERT INTO currentclient (clientcode, service_start_date, service_stop_date, notes, smart_step) VALUES ('$cltc', '$ssdate', Null, '$notes', '')";
$result3 = mysqli_query($dbci, $query3);

if ($result3 !== TRUE) 
    {
     // if error, roll back transaction
    mysqli_rollback($dbci);
    $errors[] = 'Transaction Error - No current client record could be added  '.$query3;
    }

$query2 = "INSERT INTO projectclient (clientcode, service_start_date, start_date, keyworker, stop_date, notes, project_name, ReferralSource) VALUES ('$cltc', '$ssdate', '$ssdate', '$keyworker', Null, '$notes2', '$project', '$referralsource' )";
$result2 = mysqli_query($dbci, $query2); //Run the query

if ($result2 !== TRUE) {
     // if error, roll back transaction
    mysqli_rollback($dbci);    
    $errors[] = 'Transaction Error - No project client recordcould be added  '.$query2;
    }

$query4 = "UPDATE eduemp_initialassessment SET project_start_date ='$ssdate'WHERE clientcode = '$id' AND date_issued = '$reqdate'";
$result4 = mysqli_query($dbci, $query4); //Run the query
	
if ($result4 !== TRUE) {
    // if error, roll back transaction
    mysqli_rollback($dbci);
    $errors[] = 'Transaction Error - the education and employment assessment record could not be updated  '.$query4;
    }
	
	
	
if (empty($errors))
{ // It ran ok.
		
mysqli_commit($dbci);    

echo '<h1 id=mainhead> Current Client Added </h1>' ;
echo 'You have successfully added a Current Client Record for Client No.' . $cltc . ' ' . $fname .' ' . $lname .
          ' with a Service Start Date: ' . $dy .'-'. $mnth .'-'.$yr;
echo '<br><br><center><input type=button onClick="winrefresh();" value="Close"></center>';
exit();

} else 
{
    //include error handling which takes $errors from errors[] value as message.
    include ('../includes/errorHandle.php');
}

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Question by:EICT
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6 Comments
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 40231386
are the tables all of engine type "InnoDB"? if they are not (typically MyISAM), transactions won't work, see here:
http://dev.mysql.com/doc/refman/5.0/en/storage-engines.html
0
 

Author Comment

by:EICT
ID: 40231724
Hi Guy,
They are all InnoDB tables. I wondered if there was something wrong with the logic of my code?

Thanks
0
 
LVL 143

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 300 total points
ID: 40231781
yes, you have the code like this.

run query1
if NOT OK => rollback

run query2
if NOT OK => rollback

run query3
if NOT OK => rollback

commit

this means that if query1 fails, rollback is raised (though actually not needed there as it failed), and then you continue processing query2 and query3 , which may run without errors and hence get comitted at the end


you will need to fully stop processing then next queries as soon as any of the previous ones failed ( use
if (empty($errors))  before all of them ) , or do the rollback at the end, and not at each step
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Author Comment

by:EICT
ID: 40231835
Ok I think I see what is happening here.  query1 fails so is rolledback. Processing continues query 2 & 3 run without errors and are therefore committed. So the roll back needs to be at the end of all/any query error.

Not quite sure why but when I tested it -  if there was an error in query 2, query 1 was still committed.
0
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 40236146
not sure, but please restructure the code anyhow as suggested...
0
 

Author Closing Comment

by:EICT
ID: 40238768
Thanks. I removed my roll back from each query check and placed it at the end.  I'm not sure if you actually need explicit roll back because the commit statement will never be run if there is an error.  What do you think?

if (empty($errors))
{ // It ran ok.
mysqli_commit($dbci);    
//do some other stuff here....
exit();

} else
{mysqli_rollback($dbci);
 //include error handling which takes $errors from errors[] value as message.
 include ('../includes/errorHandle.php');
 }
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