Simple database application.

Hi, I need functionality for a simple database application written in plain PHP and MySQL. I have supplied database structure and basic php files with some static information. This is to help you visualize what is required. Your task is to modify supplied files (create additional files where necessary) to enable the functionality. Additional requirements: 1. Saving data to database must be done in a separate file, later you can use headers("location:") to redirect back. 2. Validation required for numeric values and mandatory fields. 3. Create Login screen and hold logged in user in session variable. Each user has its own list of customers. 4. Create user admin, which cannot be deleted. 5. Ignore Bulk Load menu item. Database holds the list of machines and their parts in the same table. If a record has field - products_id set - that means it is a part belonging to this machine. If field products_id is NULL then this is the machine. So table products has a relational link to itself. Please ask questions if something is not clear.