Add the :eager_graph association option, works just like :eager excep…

…t it uses #eager_graph

This doesn't work perfectly yet, as the association filters don't use
qualified columns.  That will be fixed in a later commit.

sequel/CHANGELOG

@@ -1,5 +1,7 @@
 === HEAD
 
+* Add the :eager_graph association option, works just like :eager except it uses #eager_graph (jeremyevans)
+
 * Make eager loading via #eager respect the :limit association option (jeremyevans)
 
 * Add :graph_join_table_join_type association option (jeremyevans)

sequel/lib/sequel_model/associations.rb

@@ -87,7 +87,11 @@ def all_association_reflections
   #   - :class - The associated class or its name. If not
   #     given, uses the association's name, which is camelized (and
   #     singularized unless the type is :many_to_one)
-  #   - :eager - The associations to eagerly load when loading the associated object.
+  #   - :eager - The associations to eagerly load via EagerLoading#eager when loading the associated object(s).
+  #     For many_to_one associations, this is ignored unless this association is
+  #     being eagerly loaded, as it doesn't save queries unless multiple objects
+  #     can be loaded at once.
+  #   - :eager_graph - The associations to eagerly load via EagerLoading#eager_graph when loading the associated object(s).
   #     For many_to_one associations, this is ignored unless this association is
   #     being eagerly loaded, as it doesn't save queries unless multiple objects
   #     can be loaded at once.
@@ -244,6 +248,7 @@ def def_association_dataset_methods(name, opts, &block)
     dataset_block = opts[:block]
     order = opts[:order]
     eager = opts[:eager]
+    eager_graph = opts[:eager_graph]
     limit = opts[:limit]
 
     # If a block is given, define a helper method for it, because it takes
@@ -260,6 +265,7 @@ def def_association_dataset_methods(name, opts, &block)
       ds = ds.order(*order) if order
       ds = ds.limit(*limit) if limit
       ds = ds.eager(eager) if eager
+      ds = ds.eager_graph(eager_graph) if eager_graph
       ds = send(helper_method, ds) if dataset_block
       ds
     end

sequel/lib/sequel_model/eager_loading.rb

@@ -371,6 +371,7 @@ def eager_load(a)
       assoc_block = Proc.new do |d|
         d = d.order(*reflection[:order]) if reflection[:order]
         d = d.limit(*reflection[:limit]) if reflection[:limit]
+        d = d.eager_graph(reflection[:eager_graph]) if reflection[:eager_graph]
         d = d.eager(reflection[:eager]) if reflection[:eager]
         d = d.eager(eager_assoc[assoc_name]) if eager_assoc[assoc_name]
         d = reflection[:eager_block].call(d) if reflection[:eager_block]

sequel/spec/eager_loading_spec.rb

@@ -20,6 +20,7 @@ class EagerAlbum < Sequel::Model(:albums)
     class EagerBand < Sequel::Model(:bands)
       columns :id
       one_to_many :albums, :class=>'EagerAlbum', :key=>:band_id, :eager=>:tracks
+      one_to_many :graph_albums, :class=>'EagerAlbum', :key=>:band_id, :eager_graph=>:tracks
       many_to_many :members, :class=>'EagerBandMember', :left_key=>:band_id, :right_key=>:member_id, :join_table=>:bm
       one_to_many :good_albums, :class=>'EagerAlbum', :key=>:band_id, :eager_block=>proc{|ds| ds.filter(:name=>'good')} do |ds|
         ds.filter(:name=>'Good')
@@ -47,6 +48,10 @@ class EagerBandMember < Sequel::Model(:members)
     end
 
     EagerAlbum.dataset.extend(Module.new {
+      def columns
+        [:id, :band_id]
+      end
+
       def fetch_rows(sql)
         h = if sql =~ /101/
           {:id => 101, :band_id=> 101}
@@ -238,6 +243,62 @@ def fetch_rows(sql)
     MODEL_DB.sqls.length.should == 3
   end
 
+  it "should cascade eagerly loading when the :eager_graph association option is used" do
+    EagerAlbum.dataset.extend(Module.new {
+      def fetch_rows(sql)
+        @db << sql
+        yield({:id=>1, :band_id=>2, :tracks_id=>3, :album_id=>1})
+      end
+    })
+    a = EagerBand.eager(:graph_albums).all
+    a.should be_a_kind_of(Array)
+    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', 
+                             '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) WHERE (band_id IN (2))']
+    a = a.first
+    a.graph_albums.should be_a_kind_of(Array)
+    a.graph_albums.size.should == 1
+    a.graph_albums.first.should be_a_kind_of(EagerAlbum)
+    a.graph_albums.first.values.should == {:id => 1, :band_id => 2}
+    a = a.graph_albums.first
+    a.tracks.should be_a_kind_of(Array)
+    a.tracks.size.should == 1
+    a.tracks.first.should be_a_kind_of(EagerTrack)
+    a.tracks.first.values.should == {:id => 3, :album_id => 1}
+    MODEL_DB.sqls.length.should == 2
+  end
+
+  it "should respect :eager_graph when lazily loading an association" do
+    a = EagerBand.all
+    a.should be_a_kind_of(Array)
+    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
+    EagerAlbum.dataset.extend(Module.new {
+      def fetch_rows(sql)
+        @db << sql
+        yield({:id=>1, :band_id=>2, :tracks_id=>3, :album_id=>1})
+      end
+    })
+    a.graph_albums
+    MODEL_DB.sqls.should == ['SELECT * FROM bands', 
+                             '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) WHERE (band_id = 2)']
+    a.graph_albums.should be_a_kind_of(Array)
+    a.graph_albums.size.should == 1
+    a.graph_albums.first.should be_a_kind_of(EagerAlbum)
+    a.graph_albums.first.values.should == {:id => 1, :band_id => 2}
+    a = a.graph_albums.first
+    a.tracks.should be_a_kind_of(Array)
+    a.tracks.size.should == 1
+    a.tracks.first.should be_a_kind_of(EagerTrack)
+    a.tracks.first.values.should == {:id => 3, :album_id => 1}
+    MODEL_DB.sqls.length.should == 2
+  end
+
   it "should respect :order when eagerly loading" do
     a = EagerBandMember.eager(:bands).all
     a.should be_a_kind_of(Array)