basic implementation of in memory insertions

Conflicts:

	lib/arel/engines/memory/relations.rb

doc/TODO

@@ -1,11 +1,12 @@
 todo:
-- fix AR
+- insertions for in memory
 - cross-engine joins
 - blocks for joins
-- deal with table tests in algebra
+- test sql insertions 
 - implement mnesia adapter
-- rename externalize to derived.
 
+- rename externalize to derived.
+- deal with table tests in algebra
 - fix grouping
 - audit unit coverage of algebra
 - data objects
@@ -92,6 +93,7 @@ done:
 - result sets to attr correlation too
 - implement joins in memory
 - result sets should be array relations
+- fix AR
 
 icebox:
 - #bind in Attribute and Expression should be doing a descend?

lib/arel/algebra/relations/relation.rb

@@ -57,7 +57,7 @@ module Arel
 
       module Writable
         def insert(record)
-          session.create Insert.new(self, record); self
+          session.create Insert.new(self, record)
         end
 
         def update(assignments)

lib/arel/engines/memory/engine.rb

@@ -5,6 +5,10 @@ module Arel
         def read(relation)
           relation.eval
         end
+        
+        def create(relation)
+          relation.eval
+        end
       end
       include CRUD
     end

lib/arel/engines/memory/relations.rb

@@ -1,4 +1,5 @@
 require 'arel/engines/memory/relations/array'
 require 'arel/engines/memory/relations/operations'
+require 'arel/engines/memory/relations/writes'
 require 'arel/engines/memory/relations/compound'
 

lib/arel/engines/memory/relations/writes.rb

@@ -0,0 +1,7 @@
+module Arel
+  class Insert < Compound
+    def eval
+      unoperated_rows + [Row.new(self, record.values.collect(&:value))]  
+    end
+  end
+end

lib/arel/session.rb

@@ -24,6 +24,7 @@ module Arel
     module CRUD
       def create(insert)
         insert.call
+        insert
       end
 
       def read(select)
@@ -34,10 +35,12 @@ module Arel
 
       def update(update)
         update.call
+        update
       end
 
       def delete(delete)
         delete.call
+        delete
       end
     end
     include CRUD

spec/arel/engines/memory/unit/relations/insert_spec.rb

@@ -0,0 +1,28 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Insert do
+    before do
+      @relation = Array.new([
+        [1, 'duck' ],
+        [2, 'duck' ],
+        [3, 'goose']
+      ], [:id, :name])
+    end
+    
+    describe '#call' do
+      it "manufactures an array of hashes of attributes to values" do
+        @relation                                                         \
+          .insert(@relation[:id] => 4, @relation[:name] => 'guinea fowl') \
+        .let do |relation|
+          relation.call.should == [
+            Row.new(relation, [1, 'duck']),
+            Row.new(relation, [2, 'duck']),
+            Row.new(relation, [3, 'goose']),
+            Row.new(relation, [4, 'guinea fowl'])
+          ]
+        end
+      end
+    end
+  end
+end