Rails specifies conventions while creating models, controllers, migrations ( database tables ).
Conventions for creating database tables
1. Table name should be plural
2. id field should be primary_key for table.
3. foreign_key should be like _id i.e. post_id, site_id
Conventions for creating models & Controllers
1. Model name should be singular
2. controller name should be plural.
Although rails has standard defined, In some cases it becomes quite necessary to map irregular
1. Table mapping
class Review < ActiveRecord::Base
# Here comments is name of database table
set_table_name :comments
end
2. Set primary key ( other than rails standar 'id' primary_key )
class Review < ActiveRecord::Base
# It assumes "reviews" as table in database
# Below line indicates reviews table contains column_name "reviewId" which is a primary_key
set_primary_key :reviewId
end
3. Foreign key association
class Review < ActiveRecord::Base
# Below line indicates reviews table contains column_name 'RatingId' which is foreign_key to primary_key
# of 'ratings' table.
# It can be applied to any associan type [ has_one, has_many, belongs_to, has_many_through ]
belongs_to :rating, :class_name => "SiteUser", :foreign_key => "RatingId"
end
4. Model association ( non-standard model name )
class Review < ActiveRecord::Base
# Below line indicates reviews table contains column_name 'UserId' which is foreign_key to primary_key
# of model with class_name 'SiteUser'
belongs_to :user, :class_name => 'SiteUser', :foreign_key: => 'UserId'
end
