123456789_123456789_123456789_123456789_123456789_

Class: ActiveRecord::QueryMethods::WhereChain

Relationships & Source Files
Inherits: Object
Defined in: activerecord/lib/active_record/relation/query_methods.rb

Overview

WhereChain objects act as placeholder for queries in which #where does not have any parameter. In this case, #where can be chained to return a new relation.

Class Method Summary

Instance Method Summary

Constructor Details

.new(scope) ⇒ WhereChain

This method is for internal use only.
[ GitHub ] 

  


# File 'activerecord/lib/active_record/relation/query_methods.rb', line 15



def initialize(scope) # :nodoc:
  @scope = scope
end


  







Instance Method Details



  

    #associated(*associations)  
  



  

    
Returns a new relation with joins and where clause to identify
associated relations.


For example, posts that are associated to a related author:


{Post.where}.associated(:author)
#### SELECT "posts".* FROM "posts"
#### INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
#### WHERE "authors"."id" IS NOT NULL


Additionally, multiple relations can be combined. This will return posts
associated to both an author and any comments:


{Post.where}.associated(:author, :comments)
#### SELECT "posts".* FROM "posts"
#### INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
#### INNER JOIN "comments" ON "comments"."post_id" = "posts"."id"
#### WHERE "authors"."id" IS NOT NULL AND "comments"."id" IS NOT NULL


You can define join type in the scope and associated will not use JOIN by default.


{Post.left_joins}(:author).where.associated(:author)
#### SELECT "posts".* FROM "posts"
#### LEFT OUTER JOIN "authors" ON "authors"."id" = "posts"."author_id"
#### WHERE "authors"."id" IS NOT NULL

{Post.left_joins}(:comments).where.associated(:author)
#### SELECT "posts".* FROM "posts"
#### INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
#### LEFT OUTER JOIN "comments" ON "comments"."post_id" = "posts"."id"
#### WHERE "authors"."id" IS NOT NULL

  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/relation/query_methods.rb', line 99



def associated(*associations)
  associations.each do |association|
    reflection = scope_association_reflection(association)
    unless @scope.joins_values.include?(reflection.name) || @scope.left_outer_joins_values.include?(reflection.name)
      @scope.joins!(association)
    end

    association_conditions = reflection.association_primary_key_definition.index_with(nil)
    if reflection.options[:class_name]
      self.not(association => association_conditions)
    else
      self.not(reflection.table_name => association_conditions)
    end
  end

  @scope
end


  








  

    #missing(*associations)  
  



  

    
Returns a new relation with left outer joins and where clause to identify
missing relations.


For example, posts that are missing a related author:


{Post.where}.missing(:author)
#### SELECT "posts".* FROM "posts"
#### LEFT OUTER JOIN "authors" ON "authors"."id" = "posts"."author_id"
#### WHERE "authors"."id" IS NULL


Additionally, multiple relations can be combined. This will return posts
that are missing both an author and any comments:


{Post.where}.missing(:author, :comments)
#### SELECT "posts".* FROM "posts"
#### LEFT OUTER JOIN "authors" ON "authors"."id" = "posts"."author_id"
#### LEFT OUTER JOIN "comments" ON "comments"."post_id" = "posts"."id"
#### WHERE "authors"."id" IS NULL AND "comments"."id" IS NULL

  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/relation/query_methods.rb', line 139



def missing(*associations)
  associations.each do |association|
    reflection = scope_association_reflection(association)
    @scope.left_outer_joins!(association)
    association_conditions = reflection.association_primary_key_definition.index_with(nil)
    if reflection.options[:class_name]
      @scope.where!(association => association_conditions)
    else
      @scope.where!(reflection.table_name => association_conditions)
    end
  end

  @scope
end


  








  

    #not(opts, *rest)  
  



  

    
Returns a new relation expressing WHERE + NOT condition according to
the conditions in the arguments.


#not accepts conditions as a string, array, or hash. See ActiveRecord::QueryMethods#where for
more details on each format.


{User.where}.not("name = 'Jon'")
#### SELECT * FROM users WHERE NOT (name = 'Jon')

{User.where}.not(["name = ?", "Jon"])
#### SELECT * FROM users WHERE NOT (name = 'Jon')

{User.where}.not(name: "Jon")
#### SELECT * FROM users WHERE name != 'Jon'

{User.where}.not(name: nil)
#### SELECT * FROM users WHERE name IS NOT NULL

{User.where}.not(name: %w(Ko1 Nobu))
#### SELECT * FROM users WHERE name NOT IN ('Ko1', 'Nobu')

{User.where}.not(name: "Jon", role: "admin")
#### SELECT * FROM users WHERE NOT (name = 'Jon' AND role = 'admin')


If there is a non-nil condition on a nullable column in the hash condition, the records that have
nil values on the nullable column won't be returned.


{User.create!}(nullable_country: nil)
{User.where}.not(nullable_country: "UK")
#### SELECT * FROM users WHERE NOT (nullable_country = 'UK')
#### => []

  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/relation/query_methods.rb', line 54



def not(opts, *rest)
  where_clause = @scope.send(:build_where_clause, opts, rest)

  @scope.where_clause += where_clause.invert

  @scope
end


  








  

    #scope_association_reflection(association)   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/relation/query_methods.rb', line 155



def scope_association_reflection(association)
  model = @scope.model
  reflection = model._reflect_on_association(association)
  unless reflection
    raise ArgumentError.new("An association named `:#{association}` does not exist on the model `#{model.name}`.")
  end
  reflection
end