Manipulate Database from Drupal
Drupal isn't an MVC framework.

Content types and entities give you a way to insert records into a database, and edit them as well.

Making a "view" of one kind of record is possible with the Views module, and also the VBO module.

Deleting "related things" is trickier and requires the use of built-in hooks to remove related items from the database typically. Or if using Entities you could wire removing relationships into the Entity Controller.

Simply put, Drupal isn't a Ruby on Rails-like framework where you get CRUD capability for free; it currently acts more like the Linux kernel (in my opinion) where you register or "hook-into" the lifecycle of a thing and alter it to your needs.

You may find these 2 modules useful:


Model Entities uses Entities to kind of create a CRUD like interfaces for custom objects built with D7 Entity(s).
SBDO an ORM for custom object tables in drupal