Patched Arel v2.0.6 to support MSSQL SQL queries. Based on work of James Abley (https://github.com/jabley/arel).

10 files changed, 54 insertions, 7 deletions

diff --git a/lib/arel/nodes.rb b/lib/arel/nodes.rb
index c454152d0d..db2f22750a 100644
--- a/lib/arel/nodes.rb
+++ b/lib/arel/nodes.rb
@@ -24,6 +24,8 @@ require 'arel/nodes/function'
 require 'arel/nodes/count'
 require 'arel/nodes/values'
 require 'arel/nodes/offset'
+require 'arel/nodes/limit'
+require 'arel/nodes/top'
 require 'arel/nodes/sum'
 require 'arel/nodes/exists'
 require 'arel/nodes/max'
diff --git a/lib/arel/nodes/limit.rb b/lib/arel/nodes/limit.rb
new file mode 100644
index 0000000000..68ea95daf5
--- /dev/null
+++ b/lib/arel/nodes/limit.rb
@@ -0,0 +1,7 @@
+module Arel
+  module Nodes
+    class Limit < Arel::Nodes::Unary
+    end
+  end
+end
+
diff --git a/lib/arel/nodes/select_core.rb b/lib/arel/nodes/select_core.rb
index acc6bb9815..501a2aaf7c 100644
--- a/lib/arel/nodes/select_core.rb
+++ b/lib/arel/nodes/select_core.rb
@@ -1,10 +1,11 @@
 module Arel
   module Nodes
     class SelectCore < Arel::Nodes::Node
-      attr_accessor :froms, :projections, :wheres, :groups
+      attr_accessor :top, :froms, :projections, :wheres, :groups
       attr_accessor :having
 
       def initialize
+        @top         = nil
         @froms       = nil
         @projections = []
         @wheres      = []
diff --git a/lib/arel/nodes/top.rb b/lib/arel/nodes/top.rb
new file mode 100644
index 0000000000..56e2e97e8d
--- /dev/null
+++ b/lib/arel/nodes/top.rb
@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class Top < Arel::Nodes::Unary
+    end
+  end
+end
diff --git a/lib/arel/select_manager.rb b/lib/arel/select_manager.rb
index 10d23378ae..cb656d5340 100644
--- a/lib/arel/select_manager.rb
+++ b/lib/arel/select_manager.rb
@@ -10,7 +10,7 @@ module Arel
     end
 
     def taken
-      @ast.limit
+      @ast.limit && @ast.limit.expr
     end
 
     def constraints
@@ -131,7 +131,8 @@ module Arel
     end
 
     def take limit
-      @ast.limit = limit
+      @ast.limit = Nodes::Limit.new(limit)
+      @ctx.top   = Nodes::Top.new(limit)
       self
     end
 
diff --git a/lib/arel/visitors.rb b/lib/arel/visitors.rb
index 2b0a06d534..8410b2b912 100644
--- a/lib/arel/visitors.rb
+++ b/lib/arel/visitors.rb
@@ -4,6 +4,7 @@ require 'arel/visitors/to_sql'
 require 'arel/visitors/sqlite'
 require 'arel/visitors/postgresql'
 require 'arel/visitors/mysql'
+require 'arel/visitors/mssql'
 require 'arel/visitors/oracle'
 require 'arel/visitors/join_sql'
 require 'arel/visitors/where_sql'
@@ -16,6 +17,8 @@ module Arel
       'postgresql'      => Arel::Visitors::PostgreSQL,
       'mysql'           => Arel::Visitors::MySQL,
       'mysql2'          => Arel::Visitors::MySQL,
+      'mssql'           => Arel::Visitors::MSSQL,
+      'sqlserver'       => Arel::Visitors::MSSQL,
       'oracle_enhanced' => Arel::Visitors::Oracle,
       'sqlite'          => Arel::Visitors::SQLite,
       'sqlite3'         => Arel::Visitors::SQLite,
diff --git a/lib/arel/visitors/mssql.rb b/lib/arel/visitors/mssql.rb
new file mode 100644
index 0000000000..9b0e77c19b
--- /dev/null
+++ b/lib/arel/visitors/mssql.rb
@@ -0,0 +1,16 @@
+module Arel
+  module Visitors
+    class MSSQL < Arel::Visitors::ToSql
+      private
+
+      def visit_Arel_Nodes_Limit o
+        ""
+      end
+
+      def visit_Arel_Nodes_Top o
+        "TOP #{visit o.expr}"
+      end
+
+    end
+  end
+end
diff --git a/lib/arel/visitors/mysql.rb b/lib/arel/visitors/mysql.rb
index ace8fb0979..b37d76f710 100644
--- a/lib/arel/visitors/mysql.rb
+++ b/lib/arel/visitors/mysql.rb
@@ -10,7 +10,7 @@ module Arel
       # :'(
       # http://dev.mysql.com/doc/refman/5.0/en/select.html#id3482214
       def visit_Arel_Nodes_SelectStatement o
-        o.limit = 18446744073709551615 if o.offset && !o.limit
+        o.limit = Arel::Nodes::Limit.new(18446744073709551615) if o.offset && !o.limit
         super
       end
 
diff --git a/lib/arel/visitors/sqlite.rb b/lib/arel/visitors/sqlite.rb
index c45160851d..237ae913bb 100644
--- a/lib/arel/visitors/sqlite.rb
+++ b/lib/arel/visitors/sqlite.rb
@@ -3,7 +3,7 @@ module Arel
     class SQLite < Arel::Visitors::ToSql
       private
       def visit_Arel_Nodes_SelectStatement o
-        o.limit = -1 if o.offset && !o.limit
+        o.limit = Arel::Nodes::Limit.new(-1) if o.offset && !o.limit
         super
       end
     end
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index a2105d7043..7435e41561 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -76,7 +76,7 @@ module Arel
         [
           o.cores.map { |x| visit_Arel_Nodes_SelectCore x }.join,
           ("ORDER BY #{o.orders.map { |x| visit x }.join(', ')}" unless o.orders.empty?),
-          ("LIMIT #{visit o.limit}" if o.limit),
+          (visit(o.limit) if o.limit),
           (visit(o.offset) if o.offset),
           (visit(o.lock) if o.lock),
         ].compact.join ' '
@@ -84,7 +84,9 @@ module Arel
 
       def visit_Arel_Nodes_SelectCore o
         [
-          "SELECT #{o.projections.map { |x| visit x }.join ', '}",
+          "SELECT",
+          (visit(o.top) if o.top),
+          "#{o.projections.map { |x| visit x }.join ', '}",
           ("FROM #{visit o.froms}" if o.froms),
           ("WHERE #{o.wheres.map { |x| visit x }.join ' AND ' }" unless o.wheres.empty?),
           ("GROUP BY #{o.groups.map { |x| visit x }.join ', ' }" unless o.groups.empty?),
@@ -100,6 +102,15 @@ module Arel
         "OFFSET #{visit o.expr}"
       end
 
+      def visit_Arel_Nodes_Limit o
+        "LIMIT #{visit o.expr}"
+      end
+
+      # FIXME: this does nothing on most databases, but does on MSSQL
+      def visit_Arel_Nodes_Top o
+        ""
+      end
+
       # FIXME: this does nothing on SQLLite3, but should do things on other
       # databases.
       def visit_Arel_Nodes_Lock o