Question

I have a table on MySQL with a primary key, I inserted to that table and I want to resume the id of the last row has inserted, I know I have to use LAST_INSERT_ID
but my question is after using that statement to insert values to another table that doesn’t have primary key , can I use it again to get the exact ID of the first inserted ?

$php pdo #

include_once 'type_model.php';
        $t = new Type_Model();
        $typeID = $t->getTypeID($type);
        include_once 'informationObject_model.php';
        $i = new InformationObject_Model();
        $answerIoID = $i->getIOID($ioAnswer);
        $query = "INSERT INTO question (info, text, answer, answerIoID, firstChoice, secondChoice, thirdChoice, 
            firstHint, secondHint, typeID) VALUES (:info, :text, :answer, :answerIoID,
            :firstChoice, :secondChoice, :thirdChoice, :firstHint, :secondHint, :typeID)";
        $sth = $this->db->prepare($query);
        $sth->execute(array(
            ':info' => $info,
            ':text' => $text,
            ':answer' => $answer,
            ':answerIoID' => $answerIoID,
            ':firstChoice' => $choices[0],
            ':secondChoice' => $choices[1],
            ':thirdChoice' => $choices[2],
            ':firstHint' => $hints[0],
            ':secondHint' => $hints[1],
            ':typeID' => $typeID
        ));
        if ($about == "Place") {
            include_once 'place_model.php';
            $p = new Place_Model();
            $placeID = $p->getPlaceID($place);
            $query = "INSERT INTO `question-place` (questionID, placeID) VALUES
                (LAST_INSERT_ID() ,:placeID )";
            $sth = $this->db->prepare($query);
            $sth->execute(array(
                ':placeID' => $placeID
            ));
        }

and now if the about==place can i write this ?

$query = "INSERT INTO `question-io` (questionID, io) VALUES
                (LAST_INSERT_ID() ,:io )";
$sth = $this->db->prepare($query);
$sth->execute(array(
                ':io' => $io
            ));

I didn’t try it , because I can’t try it untill I fill all my tables and I can’t fill all my tables without know the ID 🙂

Answer 1

if your object $this->db reference to a PDO object so you can use this

$ID=$this->db->lastInsertId();

to save your ID, it is better to save it in a variable

so after each insert you can save the ID of that inserted row

and remember you have to used it exactly after $sth->execute()