Rails'in .Where() nitelik ı <code>current_revision</code> ile <code>SectionRevision</code> ile ilişkilidir birçok <code>Section</code> modelleri içeren <code>Page</code> modele sahip

Question

NULL DEĞİLDİR. Page modelinden, current_revision.parent_section_id öğesinin sıfır olmadığı tüm Sections'u seçmeye çalışıyorum.

Section modeli:

class Section < ActiveRecord::Base 
    belongs_to :page 
    has_many :revisions, :class_name => 'SectionRevision', :foreign_key => 'section_id' 
    has_many :references 

    has_many :revisions, :class_name => 'SectionRevision', 
         :foreign_key => 'section_id' 
    belongs_to :current_revision, :class_name => 'SectionRevision', :foreign_key => 'current_revision_id' 

    delegate :position, to: :current_revision 

    def set_current_revision 
    self.current_revision = self.revisions.order('created_at DESC').first 
    end 

    def children 
    Section.includes(:current_revision).where(:section_revisions => {:parent_section_id => self.id}) 
    end 
end 

ve Page modeli:

class Page < ActiveRecord::Base 
    belongs_to :parent, :class_name => 'Page', :foreign_key => 'parent_page_id' 
    has_many :children, :class_name => 'Page', :foreign_key => 'parent_page_id' 
    belongs_to :page_image, :class_name => 'Image', :foreign_key => 'page_image_id' 
    has_many :sections 

    validates_uniqueness_of :title, :case_sensitive => false 

    def top_level_sections 
    self.sections.includes(:current_revision).where(:section_revisions => {:parent_section_id => "IS NOT NULL"}) 
    end 

end 

---

Page.top_level_sections göre yazılmıştır: şu anda Rails where condition using NOT NULL ve boş bir dizi üretir. "Parent_section_id" öğesinin boş olmadığını doğru olarak algılamaz.

Page.top_level_sections nasıl düzgün yazarım?

Answer 1

bu deneyin:

self.sections.includes(:current_revision). 
    where("section_revisions.parent_secti‌​on_id IS NOT NULL")