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@@ -14,7 +14,6 @@ users.delete().where(
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     SELECT users.*, (SELECT count(id) FROM addresses WHERE 
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     addresses.user_id=users.id) FROM users
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-- and/or w/ predicates
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 - blocks for all operations
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 - result sets to attr correlation too
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 - cache expiry on write
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@@ -23,6 +22,7 @@ users.delete().where(
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 - scoped writes
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 done:
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+- and/or w/ predicates
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 - mock out database
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 . Relation <=> Relation -> InnerJoinOperation
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 . Relation << Relation -> LeftOuterJoinOperation

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@@ -1,5 +1,12 @@
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 module Arel
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   class Predicate
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+    def or(other_predicate)
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+      Or.new(self, other_predicate)
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+    end
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+    
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+    def and(other_predicate)
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+      And.new(self, other_predicate)
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+    end
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   end
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   class Binary < Predicate
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@@ -21,6 +28,20 @@ module Arel
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     end
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     alias_method :to_s, :to_sql
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   end
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+  
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+  class CompoundPredicate < Binary
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+    def to_sql(formatter = nil)
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+      "(#{operand1.to_sql(formatter)} #{predicate_sql} #{operand2.to_sql(formatter)})"
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+    end
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+  end
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+  
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+  class Or < CompoundPredicate
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+    def predicate_sql; "OR" end
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+  end
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+  
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+  class And < CompoundPredicate
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+    def predicate_sql; "AND" end
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+  end
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   class Equality < Binary
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     def ==(other)

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@@ -13,6 +13,33 @@ module Arel
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       end
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     end
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+    describe "with compound predicates" do
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+      before do
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+        @operand1 = ConcreteBinary.new(@attribute1, 1)
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+        @operand2 = ConcreteBinary.new(@attribute2, "name")
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+      end
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+      
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+      describe Or do
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+        describe "#to_sql" do
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+          it "manufactures sql with an OR operation" do
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+            Or.new(@operand1, @operand2).to_sql.should be_like("
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+              (`users`.`id` <=> 1 OR `users`.`name` <=> 'name')
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+            ")
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+          end
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+        end
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+      end
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+
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+      describe And do
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+        describe "#to_sql" do
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+          it "manufactures sql with an AND operation" do
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+            And.new(@operand1, @operand2).to_sql.should be_like("
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+              (`users`.`id` <=> 1 AND `users`.`name` <=> 'name')
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+            ")
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+          end
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+        end
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+      end
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+    end
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+    
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     describe '#to_sql' do
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       describe 'when relating two attributes' do
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         it 'manufactures sql with a binary operation' do