Dynamic ORM Lab

Learning Goals

  • Construct an ORM superclass that can be used for multiple classes
  • Inherit the methods from the ORM class to the Student class

Dynamic ORMs & Inheritance

By this point, we've learned the value of a dynamic ORM -- a way to write an ORM that is almost entirely abstract. The key takeaway is that this ORM is not specific to any one class. The code will live in one class (the superclass) and be inherited to any class (child class) we wish to have access to the ORM methods.

Now that we've had some practice with this, let's build out a dynamic ORM that can be inherited to any class.

Let's get started

The Super Class

Make sure to run bundle install before moving on!

In the lib directory, you'll see the interactive_record.rb file. This file is where almost all of your ORM code will live. Once you set this up, you will share the methods in this class with the child class.

The Child Class

Your Student class lives in lib/student.rb. This class will inherit from InteractiveRecord. Your methods won't be written in this class. All of the methods defined in InteractiveRecord will be available to Student once you set up the inheritance.

Note: The only code the Student class needs to contain is the code to create the attr_accessors specific to itself. But even that code uses a method, #column_names, inherited from the super class.

This is a test-driven lab, so run the specs and get them to pass. (Note: You might need to install some dependencies to get the tests running — that's okay! As Jedi Master Obi-Wan Kenobi would say, "Use the Gemfile, Luke!")