From 65135d00a854edfd1684f5163db8e68fdb956ae0 Mon Sep 17 00:00:00 2001
From: Bradford Folkens <bfolkens@gmail.com>
Date: Wed, 29 Feb 2012 09:47:28 -0600
Subject: Delete should respect 'limit'

Conflicts:
	lib/arel/visitors/to_sql.rb
---
 lib/arel/crud.rb                   | 1 +
 lib/arel/delete_manager.rb         | 5 +++++
 lib/arel/nodes/delete_statement.rb | 2 ++
 lib/arel/visitors/to_sql.rb        | 6 +++---
 4 files changed, 11 insertions(+), 3 deletions(-)

(limited to 'lib')

diff --git a/lib/arel/crud.rb b/lib/arel/crud.rb
index 2dfe27445c..d310c7381f 100644
--- a/lib/arel/crud.rb
+++ b/lib/arel/crud.rb
@@ -31,6 +31,7 @@ module Arel
 
     def compile_delete
       dm = DeleteManager.new
+      dm.take @ast.limit.expr if @ast.limit
       dm.wheres = @ctx.wheres
       dm.from @ctx.froms
       dm
diff --git a/lib/arel/delete_manager.rb b/lib/arel/delete_manager.rb
index af33c60740..20e988e01f 100644
--- a/lib/arel/delete_manager.rb
+++ b/lib/arel/delete_manager.rb
@@ -11,6 +11,11 @@ module Arel
       self
     end
 
+    def take limit
+      @ast.limit = Nodes::Limit.new(Nodes.build_quoted(limit)) if limit
+      self
+    end
+
     def wheres= list
       @ast.wheres = list
     end
diff --git a/lib/arel/nodes/delete_statement.rb b/lib/arel/nodes/delete_statement.rb
index 3bac8225ec..8aaf8ca0b6 100644
--- a/lib/arel/nodes/delete_statement.rb
+++ b/lib/arel/nodes/delete_statement.rb
@@ -1,6 +1,8 @@
 module Arel
   module Nodes
     class DeleteStatement < Arel::Nodes::Binary
+      attr_accessor :limit
+
       alias :relation :left
       alias :relation= :left=
       alias :wheres :right
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index 7dfa86a575..6084f5746c 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -78,10 +78,10 @@ module Arel
         collector = visit o.relation, collector
         if o.wheres.any?
           collector << " WHERE "
-          inject_join o.wheres, collector, AND
-        else
-          collector
+          collector = inject_join o.wheres, collector, AND
         end
+
+        maybe_visit o.limit, collector
       end
 
       # FIXME: we should probably have a 2-pass visitor for this
-- 
cgit v1.2.3


From d86e20ccbea226bb6e42da508bc040fd03ab473f Mon Sep 17 00:00:00 2001
From: Tamir Duberstein <tamird@squareup.com>
Date: Mon, 23 Feb 2015 09:58:22 -0800
Subject: Special limited delete handling in MSSQL

Refernce:
https://technet.microsoft.com/en-us/library/ms175486%28v=sql.105%29.aspx
---
 lib/arel/visitors/mssql.rb  | 17 +++++++++++++++++
 lib/arel/visitors/to_sql.rb |  4 ++--
 2 files changed, 19 insertions(+), 2 deletions(-)

(limited to 'lib')

diff --git a/lib/arel/visitors/mssql.rb b/lib/arel/visitors/mssql.rb
index 7c65ad33f2..92362a0c5f 100644
--- a/lib/arel/visitors/mssql.rb
+++ b/lib/arel/visitors/mssql.rb
@@ -66,6 +66,23 @@ module Arel
         end
       end
 
+      def visit_Arel_Nodes_DeleteStatement o, collector
+        collector << 'DELETE '
+        if o.limit
+          collector << 'TOP ('
+          visit o.limit.expr, collector
+          collector << ') '
+        end
+        collector << 'FROM '
+        collector = visit o.relation, collector
+        if o.wheres.any?
+          collector << ' WHERE '
+          inject_join o.wheres, collector, AND
+        else
+          collector
+        end
+      end
+
       def determine_order_by orders, x
         if orders.any?
           orders
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index 6084f5746c..ba176a552c 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -74,10 +74,10 @@ module Arel
       end
 
       def visit_Arel_Nodes_DeleteStatement o, collector
-        collector << "DELETE FROM "
+        collector << 'DELETE FROM '
         collector = visit o.relation, collector
         if o.wheres.any?
-          collector << " WHERE "
+          collector << ' WHERE '
           collector = inject_join o.wheres, collector, AND
         end
 
-- 
cgit v1.2.3