# initialize from scratch
rails new demo && cd demo

# commit initial version (so changes are highlighted)
git add .
git commit -m "first commit"

rails generate model Student fname:string lname:string buckid:integer
# see student.rb, xxxx_create_students.rb

rails console
> Student.methods
> Student.all     # will this work?
> s = Student.new
> exit

rails db:migrate # creates schema.rb

rails console
> Student.all
> Student.all.size
> s1 = Student.new
> s2 = Student.new fname: 'Jo'
> s3 = Student.new fname: 'Primo', lname: 'Carnera'
> s2 # what is s2.buckid?
> Student.all # how many students?

> s2.save
> s3.save
> Student.all # now how many students?

> t = Student.find 1 # which one is found?
> t = Student.find_by fname: 'Primo'
> t = Student.first

######################
# Optional: seeding the database

bundle add faker

# db/seeds.rb
30.times do
  Student.create!(
    buckid: Faker::Number.unique.number(digits: 9),
    fname: Faker::Name.first_name,
    lname: Faker::Name.last_name)
end

# update database (development.sqlite3)

rails db:seed # run seeds.rb
rails db:reset # for a fresh start

rails c
> Student.all.size
> Student.last

#####################
# Add a table (:teams) an association with :students

rails generate model Team name:string

rails generate migration AddTeamToStudents team:references

rails db:drop  # clear out the old database
rails db:migrate

# student.rb
class Student < ApplicationRecord
  belongs_to :team  # note singular form
                    # adds Student#team method
end

# team.rb
class Team < ApplicationRecord
  has_many :students  # note plural form
                      # adds Team#students method
end

####################

rails c
> Student.all # no students
> Student.create fname: 'Jo' # why does this fail?

> t = Team.create name: 'Cloud Nine' 
> Student.create fname: 'Primo', team_id: 1 # set team_id directly
> Student.create lname: 'Cher', team: t # alternatively use team object
> t.students.create fname: 'Marco', lname: 'Pantani' # alternative

> Student.all
> Student.first.team
> Team.first.students

#####################
# Improve faker data to make teams too

# db/seeds.rb
6.times do
  team = Team.create(name: Faker::Team.name)
  5.times do
    team.students.create!(buckid: Faker::Number.unique.number(digits: 9),
      fname: Faker::Name.first_name,
      lname: Faker::Name.last_name)
  end
end

# update database (development.sqlite3)

rails db:seed # run seeds.rb
rails db:reset # for a fresh start

rails c
> Student.all
> Team.all
> Student.first.team
> Team.first.students

#####################
# Add validations

# models/student.rb
class Student < ApplicationRecord
    belongs_to :team
    validates :buckid, presence: true, uniqueness: true
    validates :lname, presence: true
end

# models/team.rb
class Team < ApplicationRecord
    has_many :students
    validates :name, presence: true, uniqueness: true,
      length: { minimum: 5 },
      format: { with: /\A[a-zA-Z ]+\z/, message: "only allows letters" }
end

rails c
> t = Teams.first
> t.name = t.name + '1' # append invalid character
> t.save
> t.valid?
> t.errors
> t.errors.size
> t.errors.first
> t.errors.first.message
> t.name = "test"  # too short
> t.valid?
> t.name = "tester"
> t.valid?