insert manager is starting to take shape

8 files changed, 65 insertions, 29 deletions

diff --git a/lib/arel.rb b/lib/arel.rb
index 1cca58f31b..8465d8e658 100644
--- a/lib/arel.rb
+++ b/lib/arel.rb
@@ -8,6 +8,8 @@ require 'arel/relation'
 ####
 
 require 'arel/tree_manager'
+require 'arel/insert_manager'
+require 'arel/select_manager'
 require 'arel/nodes'
 
 #### these are deprecated
diff --git a/lib/arel/insert_manager.rb b/lib/arel/insert_manager.rb
new file mode 100644
index 0000000000..bfd3034df4
--- /dev/null
+++ b/lib/arel/insert_manager.rb
@@ -0,0 +1,13 @@
+module Arel
+  class InsertManager < Arel::TreeManager
+    def initialize engine
+      super
+      @head = Nodes::InsertStatement.new
+    end
+
+    def into table
+      @head.relation = table
+      self
+    end
+  end
+end
diff --git a/lib/arel/nodes.rb b/lib/arel/nodes.rb
index 5db177d53d..eed9641bbc 100644
--- a/lib/arel/nodes.rb
+++ b/lib/arel/nodes.rb
@@ -2,3 +2,4 @@ require 'arel/nodes/equality'
 require 'arel/nodes/sql_literal'
 require 'arel/nodes/select_core'
 require 'arel/nodes/select_statement'
+require 'arel/nodes/insert_statement'
diff --git a/lib/arel/nodes/insert_statement.rb b/lib/arel/nodes/insert_statement.rb
new file mode 100644
index 0000000000..ed601aa841
--- /dev/null
+++ b/lib/arel/nodes/insert_statement.rb
@@ -0,0 +1,13 @@
+module Arel
+  module Nodes
+    class InsertStatement
+      attr_accessor :relation, :columns, :values
+
+      def initialize
+        @relation = nil
+        @columns  = []
+        @values   = []
+      end
+    end
+  end
+end
diff --git a/lib/arel/select_manager.rb b/lib/arel/select_manager.rb
new file mode 100644
index 0000000000..6420142fa0
--- /dev/null
+++ b/lib/arel/select_manager.rb
@@ -0,0 +1,29 @@
+module Arel
+  class SelectManager < Arel::TreeManager
+    def initialize engine
+      super
+      @head   = Nodes::SelectStatement.new
+      @ctx    = @head.cores.last
+    end
+
+    def from table
+      @ctx.froms << table
+      self
+    end
+
+    def project projection
+      @ctx.projections << projection
+      self
+    end
+
+    def where expr
+      @ctx.wheres << expr
+      self
+    end
+
+    def take limit
+      @head.limit = limit
+      self
+    end
+  end
+end
diff --git a/lib/arel/table.rb b/lib/arel/table.rb
index a189838c07..4269dfc62f 100644
--- a/lib/arel/table.rb
+++ b/lib/arel/table.rb
@@ -13,7 +13,7 @@ module Arel
     end
 
     def tm
-      TreeManager.new(@engine).from(self)
+      SelectManager.new(@engine).from(self)
     end
 
     def where condition
diff --git a/lib/arel/tree_manager.rb b/lib/arel/tree_manager.rb
index 9de86e2add..9dd9f27858 100644
--- a/lib/arel/tree_manager.rb
+++ b/lib/arel/tree_manager.rb
@@ -4,38 +4,12 @@ module Arel
     include Arel::Relation
 
     def initialize engine
-      @engine  = engine
-      @selects = []
-
-      # default to Select
-      @stmt = Nodes::SelectStatement.new
-      @core = @stmt.cores.last
-      @selects << @stmt
-    end
-
-    def from table
-      @core.froms << table
-      self
-    end
-
-    def project projection
-      @core.projections << projection
-      self
-    end
-
-    def where expr
-      @core.wheres << expr
-      self
-    end
-
-    def take limit
-      @stmt.limit = limit
-      self
+      @engine = engine
     end
 
     def to_sql
       viz = Visitors::ToSql.new @engine
-      viz.accept @stmt
+      viz.accept @head
     end
   end
 end
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index 2b3216abd3..7a97b0d445 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -12,6 +12,10 @@ module Arel
       end
 
       private
+      def visit_Arel_Nodes_InsertStatement o
+        "INSERT INTO #{visit o.relation}"
+      end
+
       def visit_Arel_Nodes_SelectStatement o
         [
           o.cores.map { |x| visit x }.join,