Question

Sorry for this beginners question and i’m not a PHP developer, but now i’m trying to learn it.

i want to add record in MySQL data base and i’m using transactions lock.

my code is as below.

$SqlQuery="INSERT INTO tab_photo VALUES('$PhotoID','$ProjectId','$Day','$barCode','$photoName','$PhotoXml')";

$waiting = true;
while($waiting) {
    try {
        // save border data
        $stmt = $conn->prepare($SqlQuery);
        $conn->beginTransaction();
        $stmt->execute();
        sleep(1);

        $x=$conn->commit();
        echo "x value-".$x;

        echo "Success";
        $waiting = false;
    }
    catch (PDOException $e){
        echo "Failled :".$PhotoID."-".$PhotoID;
        if(stripos($e->getMessage(), 'DATABASE IS LOCKED') !== false) {
            // This should be specific to SQLite, sleep for 0.25 seconds
            // and try again.  We do have to commit the open transaction first though
            $conn->commit();
            usleep(250000);
        } else {
            $conn->rollBack();
            throw $e;
        }
    }
}

in here as output it gives,

x value-1 Success

but actually this record doesn’t add to the database.

My Questions:

1. Even the commit is successful(output 1) how does it not added to the database?
2. how can i check whether record is added to database? ( Is there any way to find it without write select statement?

Answer 1

As I understand, you expect that PDOException will be thrown when statement is failed to execute. But as I can see, exception is not thrown by default in such cases.
See how you can change that here

Suppose in your case you should have a code like this:

$conn = new PDO($connection_string); 
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); // this will force PDO to throw exception when SQL statement fails instead of simply setting an error.

Suppose this will work fine for you.

Please note that you should not use

$SqlQuery="INSERT INTO tab_photo VALUES('$PhotoID','$ProjectId','$Day','$barCode','$photoName','$PhotoXml')";

Instead of that, you should use parameters binding:

$SqlQuery="INSERT INTO tab_photo VALUES(:PhotoID,:ProjectId,:Day,:barCode,:photoName,:PhotoXml)";
$stmt = $conn->prepare($SqlQuery);
$conn->beginTransaction();
$stmt->execute(array(':PhotoID' => $PhotoID, ':ProjectId' => $ProjectId, ....));
sleep(1);

See this for more details.