Question

I have the following code:

...
$mysqli->autocommit(FALSE);

if(in_array('files',$item)){
            $sql_el_truncate = "
                TRUNCATE TABLE `article_files`;
                TRUNCATE TABLE `files`;
                TRUNCATE TABLE `gallery_files`;
                TRUNCATE TABLE `image_captions`;
            ";

            $mysqli->multi_query($sql_el_truncate);

            do{ 
                $mysqli->use_result(); 
            }while ($mysqli->next_result()); 


            if ($mysqli->errno) { 
                $valid_entry = 0;
            } 
            echo $valid_entry;
        }

if( $valid_entry){
            $mysqli->commit();
        }else{
            $mysqli->rollback();
        }

...

On error I get a proper $valid_entry value of 0, but the rollback is not working. Even if I write on purpose some of the TRUNCATE commands falsely it will still run the rest commands, give me the error but it won’t rollback.

Anyone knows how can I properly use the transaction on the mysqli?

Answer 1

From the MySQL Reference Manual for TRUNCATE TABLE (emphasis is mine):

Logically, TRUNCATE TABLE is similar to a DELETE statement that
deletes all rows, or a sequence of DROP TABLE and CREATE TABLE
statements. To achieve high performance, it bypasses the DML method of
deleting data. Thus, it cannot be rolled back, it does not cause ON
DELETE triggers to fire, and it cannot be performed for InnoDB tables
with parent-child foreign key relationships.

If you want to be able to ROLLBACK you are going to have to use DELETE statements instead. They are less efficient here, but should give you the desired behavior.