eager_loading_spec.rb in sequel-1.5.0

- old
+ new

@@ -1,36 +1,36 @@
 require File.join(File.dirname(__FILE__), "spec_helper")
 
-describe Sequel::Model, "eager" do
+describe Sequel::Model, "#eager" do
   before(:each) do
     MODEL_DB.reset
     
     class EagerAlbum < Sequel::Model(:albums)
-      def columns; [:id, :band_id]; end
+      columns :id, :band_id
       many_to_one :band, :class=>'EagerBand', :key=>:band_id
       one_to_many :tracks, :class=>'EagerTrack', :key=>:album_id
       many_to_many :genres, :class=>'EagerGenre', :left_key=>:album_id, :right_key=>:genre_id, :join_table=>:ag
     end
 
     class EagerBand < Sequel::Model(:bands)
-      def columns; [:id]; end
+      columns :id
       one_to_many :albums, :class=>'EagerAlbum', :key=>:band_id, :eager=>:tracks
       many_to_many :members, :class=>'EagerBandMember', :left_key=>:band_id, :right_key=>:member_id, :join_table=>:bm
     end
     
     class EagerTrack < Sequel::Model(:tracks)
-      def columns; [:id, :album_id]; end
+      columns :id, :album_id
       many_to_one :album, :class=>'EagerAlbum', :key=>:album_id
     end
     
     class EagerGenre < Sequel::Model(:genres)
-      def columns; [:id]; end
+      columns :id
       many_to_many :albums, :class=>'EagerAlbum', :left_key=>:genre_id, :right_key=>:album_id, :join_table=>:ag
     end
     
     class EagerBandMember < Sequel::Model(:members)
-      def columns; [:id]; end
+      columns :id
       many_to_many :bands, :class=>'EagerBand', :left_key=>:member_id, :right_key=>:band_id, :join_table=>:bm, :order =>:id
     end
     
     EagerAlbum.dataset.extend(Module.new {
       def fetch_rows(sql)
@@ -204,11 +204,11 @@
     a.size.should == 1
     a.first.should be_a_kind_of(EagerBand)
     a.first.values.should == {:id => 2}
     MODEL_DB.sqls.should == ['SELECT * FROM bands']
     a = a.first
-    a.albums.all
+    a.albums
     MODEL_DB.sqls.should == ['SELECT * FROM bands', 
                              'SELECT * FROM albums WHERE (band_id = 2)',
                              'SELECT * FROM tracks WHERE (album_id IN (1))']
     a.albums.should be_a_kind_of(Array)
     a.albums.size.should == 1
@@ -254,7 +254,295 @@
     a.tracks.first.should be_a_kind_of(EagerTrack)
     a.tracks.first.values.should == {:id => 3, :album_id=>1}
     a.tracks.first.album.should be_a_kind_of(EagerAlbum)
     a.tracks.first.album.should == a
     MODEL_DB.sqls.length.should == 2
+  end
+end
+
+describe Sequel::Model, "#eager_graph" do
+  after(:all) do
+    class MockDataset
+      alias clone orig_clone
+    end
+  end
+
+  before(:all) do
+    class MockDataset
+      alias orig_clone clone
+      def clone(opts = {})
+        c = super()
+        c.opts = @opts.merge(opts)
+        c.instance_variable_set(:@columns, (@columns.dup if @columns))
+        c
+      end
+    end
+
+    class GraphAlbum < Sequel::Model(:albums)
+      dataset.opts[:from] = [:albums]
+      columns :id, :band_id
+      many_to_one :band, :class=>'GraphBand', :key=>:band_id
+      one_to_many :tracks, :class=>'GraphTrack', :key=>:album_id
+      many_to_many :genres, :class=>'GraphGenre', :left_key=>:album_id, :right_key=>:genre_id, :join_table=>:ag
+    end
+
+    class GraphBand < Sequel::Model(:bands)
+      dataset.opts[:from] = [:bands]
+      columns :id, :vocalist_id
+      many_to_one :vocalist, :class=>'GraphBandMember', :key=>:vocalist_id
+      one_to_many :albums, :class=>'GraphAlbum', :key=>:band_id
+      many_to_many :members, :class=>'GraphBandMember', :left_key=>:band_id, :right_key=>:member_id, :join_table=>:bm
+      many_to_many :genres, :class=>'GraphGenre', :left_key=>:band_id, :right_key=>:genre_id, :join_table=>:bg
+    end
+    
+    class GraphTrack < Sequel::Model(:tracks)
+      dataset.opts[:from] = [:tracks]
+      columns :id, :album_id
+      many_to_one :album, :class=>'GraphAlbum', :key=>:album_id
+    end
+    
+    class GraphGenre < Sequel::Model(:genres)
+      dataset.opts[:from] = [:genres]
+      columns :id
+      many_to_many :albums, :class=>'GraphAlbum', :left_key=>:genre_id, :right_key=>:album_id, :join_table=>:ag
+    end
+    
+    class GraphBandMember < Sequel::Model(:members)
+      dataset.opts[:from] = [:members]
+      columns :id
+      many_to_many :bands, :class=>'GraphBand', :left_key=>:member_id, :right_key=>:band_id, :join_table=>:bm
+    end
+  end
+    
+  it "should eagerly load a single many_to_one association" do
+    ds = GraphAlbum.eager_graph(:band)
+    ds.sql.should == 'SELECT albums.id, albums.band_id, band.id AS band_id_0, band.vocalist_id FROM albums LEFT OUTER JOIN bands band ON (band.id = albums.band_id)'
+    def ds.fetch_rows(sql, &block)
+      yield({:id=>1, :band_id=>2, :band_id_0=>2, :vocalist_id=>3})
+    end
+    a = ds.all
+    a.should be_a_kind_of(Array)
+    a.size.should == 1
+    a.first.should be_a_kind_of(GraphAlbum)
+    a.first.values.should == {:id => 1, :band_id => 2}
+    a = a.first
+    a.band.should be_a_kind_of(GraphBand)
+    a.band.values.should == {:id => 2, :vocalist_id=>3}
+  end
+
+  it "should eagerly load a single one_to_many association" do
+    ds = GraphAlbum.eager_graph(:tracks)
+    ds.sql.should == 'SELECT albums.id, albums.band_id, tracks.id AS tracks_id, tracks.album_id FROM albums LEFT OUTER JOIN tracks ON (tracks.album_id = albums.id)'
+    def ds.fetch_rows(sql, &block)
+      yield({:id=>1, :band_id=>2, :tracks_id=>3, :album_id=>1})
+    end
+    a = ds.all
+    a.should be_a_kind_of(Array)
+    a.size.should == 1
+    a.first.should be_a_kind_of(GraphAlbum)
+    a.first.values.should == {:id => 1, :band_id => 2}
+    a = a.first
+    a.tracks.should be_a_kind_of(Array)
+    a.tracks.size.should == 1
+    a.tracks.first.should be_a_kind_of(GraphTrack)
+    a.tracks.first.values.should == {:id => 3, :album_id=>1}
+  end
+
+  it "should eagerly load a single many_to_many association" do
+    ds = GraphAlbum.eager_graph(:genres)
+    ds.sql.should == 'SELECT albums.id, albums.band_id, genres.id AS genres_id FROM albums LEFT OUTER JOIN ag ON (ag.album_id = albums.id) LEFT OUTER JOIN genres ON (genres.id = ag.genre_id)'
+    def ds.fetch_rows(sql, &block)
+      yield({:id=>1, :band_id=>2, :genres_id=>4})
+    end
+    a = ds.all
+    a.should be_a_kind_of(Array)
+    a.size.should == 1
+    a.first.should be_a_kind_of(GraphAlbum)
+    a.first.values.should == {:id => 1, :band_id => 2}
+    a = a.first
+    a.genres.should be_a_kind_of(Array)
+    a.genres.size.should == 1
+    a.genres.first.should be_a_kind_of(GraphGenre)
+    a.genres.first.values.should == {:id => 4}
+  end
+
+  it "should eagerly load multiple associations" do 
+    ds = GraphAlbum.eager_graph(:genres, :tracks, :band)
+    ds.sql.should == 'SELECT albums.id, albums.band_id, genres.id AS genres_id, tracks.id AS tracks_id, tracks.album_id, band.id AS band_id_0, band.vocalist_id FROM albums LEFT OUTER JOIN ag ON (ag.album_id = albums.id) LEFT OUTER JOIN genres ON (genres.id = ag.genre_id) LEFT OUTER JOIN tracks ON (tracks.album_id = albums.id) LEFT OUTER JOIN bands band ON (band.id = albums.band_id)'
+    def ds.fetch_rows(sql, &block)
+      yield({:id=>1, :band_id=>2, :genres_id=>4, :tracks_id=>3, :album_id=>1, :band_id_0=>2, :vocalist_id=>6})
+    end
+    a = ds.all
+    a.should be_a_kind_of(Array)
+    a.size.should == 1
+    a.first.should be_a_kind_of(GraphAlbum)
+    a.first.values.should == {:id => 1, :band_id => 2}
+    a = a.first
+    a.band.should be_a_kind_of(GraphBand)
+    a.band.values.should == {:id => 2, :vocalist_id=>6}
+    a.tracks.should be_a_kind_of(Array)
+    a.tracks.size.should == 1
+    a.tracks.first.should be_a_kind_of(GraphTrack)
+    a.tracks.first.values.should == {:id => 3, :album_id=>1}
+    a.genres.should be_a_kind_of(Array)
+    a.genres.size.should == 1
+    a.genres.first.should be_a_kind_of(GraphGenre)
+    a.genres.first.values.should == {:id => 4}
+  end
+
+  it "should allow cascading of eager loading for associations of associated models" do
+    ds = GraphTrack.eager_graph(:album=>{:band=>:members})
+    ds.sql.should == 'SELECT tracks.id, tracks.album_id, album.id AS album_id_0, album.band_id, band.id AS band_id_0, band.vocalist_id, members.id AS members_id FROM tracks LEFT OUTER JOIN albums album ON (album.id = tracks.album_id) LEFT OUTER JOIN bands band ON (band.id = album.band_id) LEFT OUTER JOIN bm ON (bm.band_id = band.id) LEFT OUTER JOIN members ON (members.id = bm.member_id)'
+    def ds.fetch_rows(sql, &block)
+      yield({:id=>3, :album_id=>1, :album_id_0=>1, :band_id=>2, :members_id=>5, :band_id_0=>2, :vocalist_id=>6})
+    end
+    a = ds.all
+    a.should be_a_kind_of(Array)
+    a.size.should == 1
+    a.first.should be_a_kind_of(GraphTrack)
+    a.first.values.should == {:id => 3, :album_id => 1}
+    a = a.first
+    a.album.should be_a_kind_of(GraphAlbum)
+    a.album.values.should == {:id => 1, :band_id => 2}
+    a.album.band.should be_a_kind_of(GraphBand)
+    a.album.band.values.should == {:id => 2, :vocalist_id=>6}
+    a.album.band.members.should be_a_kind_of(Array)
+    a.album.band.members.size.should == 1
+    a.album.band.members.first.should be_a_kind_of(GraphBandMember)
+    a.album.band.members.first.values.should == {:id => 5}
+  end
+  
+  it "should populate the reciprocal many_to_one association when eagerly loading the one_to_many association" do
+    MODEL_DB.reset
+    ds = GraphAlbum.eager_graph(:tracks)
+    ds.sql.should == 'SELECT albums.id, albums.band_id, tracks.id AS tracks_id, tracks.album_id FROM albums LEFT OUTER JOIN tracks ON (tracks.album_id = albums.id)'
+    def ds.fetch_rows(sql, &block)
+      @db << sql
+      yield({:id=>1, :band_id=>2, :tracks_id=>3, :album_id=>1})
+    end
+    a = ds.all
+    a.should be_a_kind_of(Array)
+    a.size.should == 1
+    a.first.should be_a_kind_of(GraphAlbum)
+    a.first.values.should == {:id => 1, :band_id => 2}
+    a = a.first
+    a.tracks.should be_a_kind_of(Array)
+    a.tracks.size.should == 1
+    a.tracks.first.should be_a_kind_of(GraphTrack)
+    a.tracks.first.values.should == {:id => 3, :album_id=>1}
+    a.tracks.first.album.should be_a_kind_of(GraphAlbum)
+    a.tracks.first.album.should == a
+    MODEL_DB.sqls.length.should == 1
+  end
+
+  it "should eager load multiple associations from the same table" do
+    ds = GraphBand.eager_graph(:vocalist, :members)
+    ds.sql.should == 'SELECT bands.id, bands.vocalist_id, vocalist.id AS vocalist_id_0, members.id AS members_id FROM bands LEFT OUTER JOIN members vocalist ON (vocalist.id = bands.vocalist_id) LEFT OUTER JOIN bm ON (bm.band_id = bands.id) LEFT OUTER JOIN members ON (members.id = bm.member_id)'
+    def ds.fetch_rows(sql, &block)
+      yield({:id=>2, :vocalist_id=>6, :vocalist_id_0=>6, :members_id=>5})
+    end
+    a = ds.all
+    a.should be_a_kind_of(Array)
+    a.size.should == 1
+    a.first.should be_a_kind_of(GraphBand)
+    a.first.values.should == {:id => 2, :vocalist_id => 6}
+    a = a.first
+    a.vocalist.should be_a_kind_of(GraphBandMember)
+    a.vocalist.values.should == {:id => 6}
+    a.members.should be_a_kind_of(Array)
+    a.members.size.should == 1
+    a.members.first.should be_a_kind_of(GraphBandMember)
+    a.members.first.values.should == {:id => 5}
+  end
+
+  it "should give you a graph of tables when called without .all" do 
+    ds = GraphAlbum.eager_graph(:band)
+    ds.sql.should == 'SELECT albums.id, albums.band_id, band.id AS band_id_0, band.vocalist_id FROM albums LEFT OUTER JOIN bands band ON (band.id = albums.band_id)'
+    def ds.fetch_rows(sql, &block)
+      yield({:id=>1, :band_id=>2, :band_id_0=>2, :vocalist_id=>3})
+    end
+    ds.first.should == {:albums=>GraphAlbum.new(:id => 1, :band_id => 2), :band=>GraphBand.new(:id => 2, :vocalist_id=>3)}
+  end
+
+  it "should not drop any associated objects if the graph could not be a cartesian product" do
+    ds = GraphBand.eager_graph(:members, :vocalist)
+    ds.sql.should == 'SELECT bands.id, bands.vocalist_id, members.id AS members_id, vocalist.id AS vocalist_id_0 FROM bands LEFT OUTER JOIN bm ON (bm.band_id = bands.id) LEFT OUTER JOIN members ON (members.id = bm.member_id) LEFT OUTER JOIN members vocalist ON (vocalist.id = bands.vocalist_id)'
+    def ds.fetch_rows(sql, &block)
+      yield({:id=>2, :vocalist_id=>6, :members_id=>5, :vocalist_id_0=>6})
+      yield({:id=>2, :vocalist_id=>6, :members_id=>5, :vocalist_id_0=>6})
+    end
+    a = ds.all
+    a.should be_a_kind_of(Array)
+    a.size.should == 1
+    a.first.should be_a_kind_of(GraphBand)
+    a.first.values.should == {:id => 2, :vocalist_id => 6}
+    a = a.first
+    a.vocalist.should be_a_kind_of(GraphBandMember)
+    a.vocalist.values.should == {:id => 6}
+    a.members.should be_a_kind_of(Array)
+    a.members.size.should == 2
+    a.members.first.should be_a_kind_of(GraphBandMember)
+    a.members.first.values.should == {:id => 5}
+    a.members.last.should be_a_kind_of(GraphBandMember)
+    a.members.last.values.should == {:id => 5}
+  end
+
+  it "should drop duplicate items that occur in sequence if the graph could be a cartesian product" do
+    ds = GraphBand.eager_graph(:members, :genres)
+    ds.sql.should == 'SELECT bands.id, bands.vocalist_id, members.id AS members_id, genres.id AS genres_id FROM bands LEFT OUTER JOIN bm ON (bm.band_id = bands.id) LEFT OUTER JOIN members ON (members.id = bm.member_id) LEFT OUTER JOIN bg ON (bg.band_id = bands.id) LEFT OUTER JOIN genres ON (genres.id = bg.genre_id)'
+    def ds.fetch_rows(sql, &block)
+      yield({:id=>2, :vocalist_id=>6, :members_id=>5, :genres_id=>7})
+      yield({:id=>2, :vocalist_id=>6, :members_id=>5, :genres_id=>8})
+      yield({:id=>2, :vocalist_id=>6, :members_id=>6, :genres_id=>7})
+      yield({:id=>2, :vocalist_id=>6, :members_id=>6, :genres_id=>8})
+    end
+    a = ds.all
+    a.should be_a_kind_of(Array)
+    a.size.should == 1
+    a.first.should be_a_kind_of(GraphBand)
+    a.first.values.should == {:id => 2, :vocalist_id => 6}
+    a = a.first
+    a.members.should be_a_kind_of(Array)
+    a.members.size.should == 2
+    a.members.first.should be_a_kind_of(GraphBandMember)
+    a.members.first.values.should == {:id => 5}
+    a.members.last.should be_a_kind_of(GraphBandMember)
+    a.members.last.values.should == {:id => 6}
+    a.genres.size.should == 2
+    a.genres.first.should be_a_kind_of(GraphGenre)
+    a.genres.first.values.should == {:id => 7}
+    a.genres.last.should be_a_kind_of(GraphGenre)
+    a.genres.last.values.should == {:id => 8}
+  end
+
+  it "should be able to be used in combination with #eager" do
+    MODEL_DB.reset
+    ds = GraphAlbum.eager_graph(:tracks).eager(:genres)
+    def ds.fetch_rows(sql, &block)
+      @db << sql
+      yield({:id=>1, :band_id=>2, :tracks_id=>3, :album_id=>1})
+    end
+    ds2 = GraphGenre.dataset
+    def ds2.fetch_rows(sql, &block)
+      @db << sql
+      yield({:id=>6, :x_foreign_key_x=>1})
+    end
+    a = ds.all
+    a.should be_a_kind_of(Array)
+    a.size.should == 1
+    a.first.should be_a_kind_of(GraphAlbum)
+    a.first.values.should == {:id => 1, :band_id => 2}
+    a = a.first
+    a.tracks.should be_a_kind_of(Array)
+    a.tracks.size.should == 1
+    a.tracks.first.should be_a_kind_of(GraphTrack)
+    a.tracks.first.values.should == {:id=>3, :album_id=>1}
+    a.genres.should be_a_kind_of(Array)
+    a.genres.size.should == 1
+    a.genres.first.should be_a_kind_of(GraphGenre)
+    a.genres.first.values.should == {:id=>6}
+    MODEL_DB.sqls[0].should == 'SELECT albums.id, albums.band_id, tracks.id AS tracks_id, tracks.album_id FROM albums LEFT OUTER JOIN tracks ON (tracks.album_id = albums.id)'
+    ["SELECT genres.*, ag.album_id AS x_foreign_key_x FROM genres INNER JOIN ag ON (ag.genre_id = genres.id) AND (ag.album_id IN (1))",
+     "SELECT genres.*, ag.album_id AS x_foreign_key_x FROM genres INNER JOIN ag ON (ag.album_id IN (1)) AND (ag.genre_id = genres.id)"
+    ].should(include(MODEL_DB.sqls[1]))
   end
 end