object-relational-mapping

Todos and Notes:

• Connect Ruby to an SQLite database
• Create database, insert data into it
• Write code that maps a Ruby class to a database table
• Write code that inserts data regarding an instance of a class into a database table row
• Build methods that read from a database table
• Build a Giraffe.all class method that returns all giraffes from the database
• Build a Giraffe.find_by_name class method that accepts one argument, a name, searches the database for a giraffe with that name and returns the matching giraffe entry if one is found
• Convert what the database gives you into a Ruby object
• Update the database to correct for wrong information using Giraffe#update.
• The #save method should not allow for duplication of the same data. In the event that an object has already been persisted in the database, the #save method should raise an exception. The #save method should check if the object has already been persisted. If so, don't INSERT a new into the database, simply update an existing one.
• How do we know if an object has already been persisted? If it has an id that is not nil. Remember that an object's id attribute gets set only once it has been INSERT-ed into the database.