CODEWITHSUNDEEP
sqlruby-on-railsactiverecord
bjorn
bjorn

Reputation: 155

Adding eager loading to custom has_many relationships

Groups and users have has_many through relationships on the table user_roles, which specifies what role users have in each group (pending, member, admin, etc). For a given group, how might I return all users matching a particular role in that group such that the code is DRY and eager loads the appropriate associations?

class Group < ActiveRecord::Base

has_many :user_roles, dependent: :destroy
has_many :users, through: :user_roles

def members(role)
  self.users.includes(:user_roles).where("user_role.role = ?", role)
  # Returns following error message:
  # PG::UndefinedTable: ERROR:  missing FROM-clause entry for table "user_role"
end

Upvotes: 0

Views: 57

Answers (1)

Exsemt
Exsemt

Reputation: 1068

Your table name probably 'user_roles' and not 'user_role'. Change the name of table in your where clause to 'user_roles'.

def members(role)
  self.users.includes(:user_roles).where("user_roles.role = ?", role)
end

Upvotes: 3

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