adding an oracle visitor

5 files changed, 31 insertions, 3 deletions

diff --git a/lib/arel/nodes.rb b/lib/arel/nodes.rb
index fade666ff7..6ed05fb31b 100644
--- a/lib/arel/nodes.rb
+++ b/lib/arel/nodes.rb
@@ -9,6 +9,7 @@ require 'arel/nodes/and'
 require 'arel/nodes/greater_than'
 require 'arel/nodes/greater_than_or_equal'
 require 'arel/nodes/less_than'
+require 'arel/nodes/less_than_or_equal'
 
 require 'arel/nodes/in'
 require 'arel/nodes/lock'
diff --git a/lib/arel/nodes/less_than_or_equal.rb b/lib/arel/nodes/less_than_or_equal.rb
new file mode 100644
index 0000000000..55449d12f1
--- /dev/null
+++ b/lib/arel/nodes/less_than_or_equal.rb
@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class LessThanOrEqual < Arel::Nodes::Binary
+    end
+  end
+end
diff --git a/lib/arel/visitors.rb b/lib/arel/visitors.rb
index 879635575b..deb4a4f991 100644
--- a/lib/arel/visitors.rb
+++ b/lib/arel/visitors.rb
@@ -1,6 +1,7 @@
 require 'arel/visitors/to_sql'
 require 'arel/visitors/postgresql'
 require 'arel/visitors/mysql'
+require 'arel/visitors/oracle'
 require 'arel/visitors/join_sql'
 require 'arel/visitors/order_clauses'
 require 'arel/visitors/dot'
@@ -8,9 +9,10 @@ require 'arel/visitors/dot'
 module Arel
   module Visitors
     VISITORS = {
-      'postgresql' => Arel::Visitors::PostgreSQL,
-      'mysql'      => Arel::Visitors::MySQL,
-      'mysql2'     => Arel::Visitors::MySQL,
+      'postgresql'      => Arel::Visitors::PostgreSQL,
+      'mysql'           => Arel::Visitors::MySQL,
+      'mysql2'          => Arel::Visitors::MySQL,
+      'oracle_enhanced' => Arel::Visitors::Oracle,
     }
 
     ENGINE_VISITORS = Hash.new do |hash, engine|
diff --git a/lib/arel/visitors/oracle.rb b/lib/arel/visitors/oracle.rb
new file mode 100644
index 0000000000..840a7a9ace
--- /dev/null
+++ b/lib/arel/visitors/oracle.rb
@@ -0,0 +1,15 @@
+module Arel
+  module Visitors
+    class Oracle < Arel::Visitors::ToSql
+      def visit_Arel_Nodes_SelectStatement o
+        if o.limit
+          o.cores.last.wheres.push Nodes::LessThanOrEqual.new(
+            Nodes::SqlLiteral.new('ROWNUM'), o.limit
+          )
+          o.limit = nil
+        end
+        super
+      end
+    end
+  end
+end
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index 69c7736a4b..5ec811a53a 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -148,6 +148,10 @@ module Arel
         "#{visit o.left} > #{visit o.right}"
       end
 
+      def visit_Arel_Nodes_LessThanOrEqual o
+        "#{visit o.left} <= #{visit o.right}"
+      end
+
       def visit_Arel_Nodes_LessThan o
         "#{visit o.left} < #{visit o.right}"
       end