INSERT INTO using PDO not inserting data - php

Question

I am trying to get the data to insert into the specified database but it just wont. Ive looked at the manual tried examples and all of that but I cant get the data to pass through to the database I can however echo/print_r/var_dump it so I know I have data. Here is my code:
public function insertJson($url, $subId)
{
$json_file = file_get_contents(KHAN_BASE.$url.'/videos');
if(isset($json_file))
{
$json_decoded = json_decode($json_file, true);
}else{
$this->error = 'A valid JSON file was not specified';
}
// var_dump($json_decoded); <--- This return all of the data needed from the json pull so i know I have data
//m3u8, mp4, png,
//". $row['m3u8'] .",". $row['mp4'] .",". $row['png'] .",
foreach($json_decoded as $row)
{
//echo $row['backup_timestamp'].'<br/>'; <--- This outputs the correct information so I know I can access it that way
$sql = "INSERT INTO tbl_khan_videos (sub_subject_id, backup_timestamp, date_added, description,
duration, extra_properties, has_questions, ka_url, keywords, kind, position, readable_id, relative_url, title, url, views,
youtube_id) VALUES (:subid, :backup_timestamp, :date_added, :description, :duration, :extra_properties, :has_questions, :ka_url, :keywords, :kind, :position,
:readable_id, :relative_url, :title, :url, :views, :youtube_id)";
$stmt = $this->db->prepare($sql);
$stmt->bindValue(":subid", $subId);
$stmt->bindValue(":backup_timestamp", $row['backup_timestamp']);
$stmt->bindValue(":date_added", $row['date_added']);
$stmt->bindValue(":description", $row['description']);
$stmt->bindValue(":duration", $row['duration']);
$stmt->bindValue(":extra_properties", $row['extra_properties']);
$stmt->bindValue(":has_questions", $row['has_questions']);
$stmt->bindValue(":ka_url", $row['ka_url']);
$stmt->bindValue(":keywords", $row['keywords']);
$stmt->bindValue(":kind", $row['kind']);
$stmt->bindValue(":position", $row['position']);
$stmt->bindValue(":readable_id", $row['readable_id']);
$stmt->bindValue(":relative_url", $row['relative_url']);
$stmt->bindValue(":title", $row['title']);
$stmt->bindValue(":url", $row['url']);
$stmt->bindValue(":views", $row['views']);
$stmt->bindValue(":youtube_id", $row['youtube_id']);
$stmt->execute();
}
}
Im not sure what I am doing wrong. I have tried binding it as an array (ex: $array = array(':subId' => $subId); $stmt->execute($array);) and still get no data through to the database. I know my config for the $this->db is good because I can pull other forms of already populated data with it. Any help would be very much appreciated.

Answer 1

I figured out my problem through some of the advice on here. What had been happening is I was trying to bind null values so the bindValue would cause the execute to go through without producing an error. Simple fix was doing this through foreach loops with a couple if statements which allowed me to set a value to the fields that were null. This solved the error. Again thank you to those who attempted to set in the correct path to finding the solution.