Raspy
Raspy provides an alternative to define and prefetch associations or relations between ActiveRecord models.
Installation
Add this line to your application's Gemfile:
gem 'raspy'And then execute:
$ bundle
Or install it yourself as:
$ gem install raspy
Usage
Here is a simple example of using the SQL DSL:
class User < ActiveRecord::Base
include Rusql
def permissions
user_permissions = table(:user_permissions)
query = select( distinct( Permission[:name] ) ).
from( Permission ).
left_outer_join( user_permissions, user_permissions[:permission_id].equals( Permission[:id] ) ).
left_outer_join( User, User[:id].equals( user_permissions[:user_id] ) ).
where( User[:id].equals(self.id) )
Permission.find_by_sql( query.to_s )
end
endHere is an advanced example of using the SQL DSL:
class User < ActiveRecord::Base
extend Rusql
def self.additional_selects
[
group_concat( distinct( Permission[:name] ) ).as( :permission_string_list )
]
end
def self.additional_joins
user_permissions = table(:user_permissions)
[
left_outer_join( user_permissions, user_permissions[:user_id].equals( User[:id] ),
left_outer_join( Permission, Permission[:id].equals( user_permissions[:permission_id] )
]
end
def permissions
self.permission_string_list.split(",")
end
def self.fetch(id:)
selects = [ User[:*].as_selector ]
selects += User.additional_selects
query = select( selects ).
from( User ).
where( User[:id].equals(id) ).
limit( 1 )
User.additional_joins.each do |j|
query = query.join( j )
end
User.find_by_sql(query.to_s).first
end
endHere's an example for the prefetch
users = User.all.to_a
[users].prefetch({
permissions: {
type: "has_and_belongs_to_many",
klass: Permission,
foreign_key: "user_id",
association_foreign_key: "permission_id",
join_table: "user_permissions",
association_condition: Permission[:deleted].equals("F")
}
})Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/sparkymat/raspy. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
License
The gem is available as open source under the terms of the MIT License.