From 8d04c28b619212f99e6ce534f75ebda59bb200a1 Mon Sep 17 00:00:00 2001
From: Yasuo Honda <yasuo.honda@gmail.com>
Date: Thu, 25 Sep 2014 19:38:35 +0900
Subject: Extract visit_Arel_Nodes_SelectOptions

---
 lib/arel/visitors/to_sql.rb | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

(limited to 'lib/arel/visitors')

diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index ba176a552c..d7ed7abd5d 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -219,11 +219,15 @@ module Arel
           }
         end
 
+        visit_Arel_Nodes_SelectOptions(o, collector)
+
+        collector
+      end
+
+      def visit_Arel_Nodes_SelectOptions o, collector
         collector = maybe_visit o.limit, collector
         collector = maybe_visit o.offset, collector
         collector = maybe_visit o.lock, collector
-
-        collector
       end
 
       def visit_Arel_Nodes_SelectCore o, collector
-- 
cgit v1.2.3


From 0e1427e917a4e47dce9f02ad9309600073622c73 Mon Sep 17 00:00:00 2001
From: Yasuo Honda <yasuo.honda@gmail.com>
Date: Tue, 4 Nov 2014 04:44:01 +0900
Subject: Create Arel::Visitors::Oracle12 to provide better top-N query to
 support `FETCH FIRST n ROWS` and `OFFSET` for Oracle 12c database

---
 lib/arel/visitors/oracle12.rb | 53 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 lib/arel/visitors/oracle12.rb

(limited to 'lib/arel/visitors')

diff --git a/lib/arel/visitors/oracle12.rb b/lib/arel/visitors/oracle12.rb
new file mode 100644
index 0000000000..4a42343c9b
--- /dev/null
+++ b/lib/arel/visitors/oracle12.rb
@@ -0,0 +1,53 @@
+module Arel
+  module Visitors
+    class Oracle12 < Arel::Visitors::ToSql
+      private
+
+      def visit_Arel_Nodes_SelectStatement o, collector
+        # Oracle does not allow LIMIT clause with select for update
+        if o.limit && o.lock
+          o = o.dup
+          o.limit = []
+        end
+
+        super
+      end
+
+      def visit_Arel_Nodes_SelectOptions o, collector
+        collector = maybe_visit o.offset, collector
+        collector = maybe_visit o.limit, collector
+        collector = maybe_visit o.lock, collector
+      end
+
+      def visit_Arel_Nodes_Limit o, collector
+        collector << "FETCH FIRST "
+        collector = visit o.expr, collector
+        collector << " ROWS ONLY"
+      end
+
+      def visit_Arel_Nodes_Offset o, collector
+        collector << "OFFSET "
+        visit o.expr, collector
+        collector << " ROWS"
+      end
+
+      def visit_Arel_Nodes_Except o, collector
+        collector << "( "
+        collector = infix_value o, collector, " MINUS "
+        collector << " )"
+      end
+
+      def visit_Arel_Nodes_UpdateStatement o, collector
+        # Oracle does not allow ORDER BY/LIMIT in UPDATEs.
+        if o.orders.any? && o.limit.nil?
+          # However, there is no harm in silently eating the ORDER BY clause if no LIMIT has been provided,
+          # otherwise let the user deal with the error
+          o = o.dup
+          o.orders = []
+        end
+
+        super
+      end
+    end
+  end
+end
-- 
cgit v1.2.3