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Froks15/Category.rb

Created April 26, 2021 17:25
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How to enforce uniqueness of the HABTM relation between category and thing on the rails side?
Raw
Category.rb
class Category < ActiveRecord::Base
has_and_belongs_to_many :things
validates :name, presence: true, uniqueness: true
end
Raw
CategoryMigration.rb
class CreateCategories < ActiveRecord::Migration
def change
create_table :categories do |t|
t.string :name
t.text :description
t.timestamps
end
add_index :categories, :name, unique: true
end
end
Raw
JoinTableMigration.rb
class CreateJoinTableCategoryThing < ActiveRecord::Migration
def change
create_join_table :categories, :things, column_options: { null: false } do |t|
t.index [:category_id, :thing_id], unique: true
t.index [:thing_id, :category_id], unique: true
end
end
end
Raw
Thing.rb
class Thing < ActiveRecord::Base
has_and_belongs_to_many :categories
validates :name, uniqueness: true
validates :name, :lat, :lng, presence: true
end
Raw
ThingMigration.rb
class CreateThings < ActiveRecord::Migration
def change
create_table :things do |t|
t.string :name
t.text :description
t.timestamps
end
add_index :things, :name, unique: true
end
end
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