Using recurssion in deleting parent and child relationship in mysql table - php

Question

I'm having trouble getting this function work. This is my database design
I'm working in an application wherein when a user deletes a parent category, all the subcategory would also be deleted, and so on and so fort..
For example:
When the user clicks on the "Test1" category in my application, the "Test1.1" and "Test1.1.1" would be deleted since it is under the "Test1" category.
This is my database design(above).
This is the code that I wrote:
function DeleteProjectPhotos( $cat_id ) {
$sql = "SELECT * FROM project_category WHERE category_id = '$cat_id'";
$query = mysql_query( $sql ) or die( mysql_error() );
if( mysql_num_rows( $query ) > 0 ) {
$sql = "SELECT * FROM project_category WHERE parent_id = '$cat_id'";
$query = mysql_query( $sql ) or die( mysql_error() );
if( mysql_num_rows( $query ) > 0 ) {
while( $row = mysql_fetch_assoc( $query ) ) {
$this->DeleteProjectPhotos( $row['category_id'] );
}
} else {
$sql = "DELETE FROM project_category WHERE category_id = '$cat_id'";
$query = mysql_query( $sql ) or die( mysql_error() );
}
}
}
But I think the whole logic here is wrong because when I try to delete the category_id 33, everything won't be deleted. Kindly teach me how to do this one.
Your help would be greatly appreciated and rewarded!
Thanks! :)

Answer 1

<?php
$catID = $_GET['catID'];
deleteCategory($catID);
function connect(){
$host = 'localhost';
$dbName = 'sony';
$userName = 'root';
$password = '';
$conn = new PDO("mysql:host=$host;dbname=$dbName",$userName,$password);
$conn->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
return $conn;
}
$stmt = '';
function deleteCategory($catID){
$conn = connect();
$tableName = 'childparent';
$sql = "select catID from $tableName where parentID = :catID";
global $stmt;
$stmt = $conn->prepare($sql);
$idsToDelete = getChilds($catID);
$idsToDelete[] = $catID;
//print_r($idsToDelete);
$delExp = '';
foreach($idsToDelete as $id)
$delExp .= " catID=$id or";
$delExp = preg_replace('/or$/','',$delExp);
if($delExp != ''){
$delSql = "delete from $tableName where $delExp";
//echo $delSql;
$delStmt = $conn->prepare($delSql);
$delStmt->execute();
}
}
$collectedIDs = array();
function getChilds($catID){
global $stmt,$collectedIDs;
$stmt->bindValue(':catID',$catID);
$stmt->execute();
$childCatIDs = array();
while($row = $stmt->fetch(pdo::FETCH_ASSOC)){
$childCatIDs[] = $row['catID'];
$collectedIDs[] = $row['catID'];
}
//print_r($childCatIDs);
//die();
if(!empty($childCatIDs)){
foreach($childCatIDs as $cid)
getChilds($cid);
}
return $collectedIDs;
}
?>

Answer 2

If you don't want triggers you can try http://php.net/manual/en/function.mysql-affected-rows.php on delete category you get it`s id and while there is a return you try to delete by cathegory or by parent