abeciana1 / ar_school

AR-Environment-Skeleton

You can use this repo to build new Activerecord projects

• You will need to create your own app/models directories

Additional Deliverables

Changing to Many-to-Many

• What changes did you make to your app? Why?

I did the remapping so that I could visually see what the new changes are.

I removed the grade_level_id columm in the teachers and students tables because GradeLevel is a now a class and instances of Teacher and Student belong to GradeLevel.

I removed the teacher_id column from the students table because changed from a has-many/belongs to association to a has-many-through association.

I created the join class model and table, GradeLevel and grade_levels respectively to reflect the new deliverables. The table was created so that it could hold students and teachers foreign keys

For macro associations, I changed the Teacher and Student classes because I needed to show that they don't have a direct or one-to-many assocation any more. The have an association through a join table.

    has_many :grade_levels
    has_many :students, through: :grade_levels

    has_many :grade_levels
    has_many :teachers, through: :grade_levels

Similarly, I added the macro association to the GradeLevel class so that instances of the Student class can access the information about Teacher class instances that are have relationship by being within the same row on the grade_levels table.

    belongs_to :student
    belongs_to :teacher

I also added ActiveRecord::Base inheritance to GradeLevel class so that the class can inherit the built-in methods that ActiveRecord has.

I edited and refactored the seed file to reflect change in associations. Otherwise there would have been argument error issues with providing more information than Ruby expected.

Additionally, I created assocation methods Teacher#students and Student#teachers because particular Student instances should know the Teacher instances that they're assocaited within grade_levels and vice versa with Teachers instance and Student instances. I also created GradeLevel.students and GradeLevel.teachers for any future class method deliverables that might require having a list of all teacher instances and student instances.

Additional Relationship

Write down deliverables for that relationship (what attributes? What class methods? What instance methods?) and then send them to me.

Questions

• Which method(s) does Active Record create for you?

  Active Record has the .all method built-in. We can also call on the attributes of our class instances like first_name and last_name because that is stored in our database and just like in OO with attr_accessors and attr_readers, we can access that information to return a certain value.

• Which method(s) did you have to create yourself? Why?

  I had to create the Teacher#tenure and the Student.all_in_grade methods.