adding not equal node, column names are expected to be symbols

7 files changed, 28 insertions, 4 deletions

diff --git a/lib/arel/attributes/attribute.rb b/lib/arel/attributes/attribute.rb
index d77574f33e..617112f681 100644
--- a/lib/arel/attributes/attribute.rb
+++ b/lib/arel/attributes/attribute.rb
@@ -1,6 +1,10 @@
 module Arel
   module Attributes
     class Attribute < Struct.new :relation, :name, :column
+      def not_eq other
+        Nodes::NotEqual.new self, other
+      end
+
       def eq other
         Nodes::Equality.new self, other
       end
diff --git a/lib/arel/compatibility/wheres.rb b/lib/arel/compatibility/wheres.rb
index eeb7a2fa38..b73b178651 100644
--- a/lib/arel/compatibility/wheres.rb
+++ b/lib/arel/compatibility/wheres.rb
@@ -8,6 +8,10 @@ module Arel
         def value
           visitor.accept self
         end
+
+        def name
+          super.to_sym
+        end
       end
 
       def initialize engine, collection
diff --git a/lib/arel/nodes.rb b/lib/arel/nodes.rb
index 1f31219417..7510214cdf 100644
--- a/lib/arel/nodes.rb
+++ b/lib/arel/nodes.rb
@@ -1,5 +1,6 @@
 require 'arel/nodes/binary'
 require 'arel/nodes/equality'
+require 'arel/nodes/not_equal'
 require 'arel/nodes/assignment'
 require 'arel/nodes/or'
 require 'arel/nodes/and'
diff --git a/lib/arel/nodes/not_equal.rb b/lib/arel/nodes/not_equal.rb
new file mode 100644
index 0000000000..7f892940cb
--- /dev/null
+++ b/lib/arel/nodes/not_equal.rb
@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class NotEqual < Arel::Nodes::Binary
+    end
+  end
+end
diff --git a/lib/arel/nodes/table_alias.rb b/lib/arel/nodes/table_alias.rb
index 4f1d70ee54..656a820a60 100644
--- a/lib/arel/nodes/table_alias.rb
+++ b/lib/arel/nodes/table_alias.rb
@@ -12,7 +12,7 @@ module Arel
       end
 
       def [] name
-        name = name.to_s
+        name = name.to_sym
         columns.find { |column| column.name == name }
       end
     end
diff --git a/lib/arel/table.rb b/lib/arel/table.rb
index 58e0c46959..efdc34ed94 100644
--- a/lib/arel/table.rb
+++ b/lib/arel/table.rb
@@ -73,12 +73,12 @@ module Arel
 
     def columns
       @columns ||= @engine.connection.columns(@name, "#{@name} Columns").map do |column|
-        Attributes.for(column).new self, column.name, column
+        Attributes.for(column).new self, column.name.to_sym, column
       end
     end
 
     def [] name
-      name = name.to_s
+      name = name.to_sym
       columns.find { |column| column.name == name }
     end
   end
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index 8638bf43c3..761f315763 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -159,7 +159,6 @@ module Arel
       def visit_Arel_Nodes_Equality o
         right = o.right
 
-        # FIXME: maybe we should visit NilClass?
         if right.nil?
           "#{visit o.left} IS NULL"
         else
@@ -167,6 +166,16 @@ module Arel
         end
       end
 
+      def visit_Arel_Nodes_NotEqual o
+        right = o.right
+
+        if right.nil?
+          "#{visit o.left} IS NOT NULL"
+        else
+          "#{visit o.left} != #{visit right}"
+        end
+      end
+
       def visit_Arel_Nodes_UnqualifiedColumn o
         "#{quote_column_name o.name}"
       end