$ this-> db-> insert_id（）似乎正在抹去我以前的insert_id变量值

Question

Here is the code:

$the_question = $_POST['question'];
            $the_answer = $_POST['answer'];
            $dummy_num[] = $_POST['dummy_answer_1'];
            $dummy_num[] = $_POST['dummy_answer_2'];
            $dummy_num[] = $_POST['dummy_answer_3'];
            //Get Hidden Test ID and Q_order
            $test_id = $_POST['test_id'];
            $q_order = $_POST['q_order'];
            //Submit Question
            $data_submit_q = array (
                'type' => 1,
                'question' => $the_question,
                'done' => 1
            );
            $this->db->where('test_id', $test_id);
            $this->db->where('q_order', $q_order);
            $this->db->update('questions', $data_submit_q);
            $question_id = $this->db->insert_id();
            $time_created = date('Y-m-d H:i:s');
            //Submit Answer 
            $data_submit_a = array (
                'test_id' => $test_id,
                'question_id' => $question_id,
                'option' => $the_answer,
                'company_id' => $data['company']->id,
                'job_id' => $data['session_job_id'],
                'time_created' => $time_created
            );
            $this->db->insert('options', $data_submit_a);
            $answer_id = $this->db->insert_id();

            //Let question know that answer is right.
            $data_submit_qr = array (
                'answer_id' => $answer_id
            );

            $this->db->where('id', $question_id);
            $this->db->where('test_id', $test_id);
            $this->db->update('questions', $data_submit_qr);

Setting the answer id removes the value of the question id, then on updating the database the answer id has no value also. Even though it does right before.

Answer 1

The method $this->db->insert_id() retrieves the ID when performing database inserts (as the name hints).

You're using it after an update, that's why your $question_id gives problems (I think it would be set to FALSE, but I don't know for sure what does that method return when called on the wrong context). WHen you do your last update you use this as a WHERE condition, and if it is not set...

It's not that your second call to insert_id() wipes out the first, I suspect is more like the first one is already NOT SET (or FALSE)