diff --git a/arangod/Aql/AstNode.cpp b/arangod/Aql/AstNode.cpp
index 142350c960..b2be001de6 100644
--- a/arangod/Aql/AstNode.cpp
+++ b/arangod/Aql/AstNode.cpp
@@ -28,6 +28,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 #include "Aql/AstNode.h"
+#include "Aql/Scopes.h"
 
 using namespace triagens::aql;
 
@@ -74,8 +75,7 @@ void AstNode::toJson (TRI_json_t* json,
   // dump node type
   TRI_Insert3ArrayJson(zone, node, "type", TRI_CreateStringCopyJson(zone, typeString().c_str()));
 
-  if (type == NODE_TYPE_VARIABLE ||
-      type == NODE_TYPE_REFERENCE ||
+  if (type == NODE_TYPE_REFERENCE ||
       type == NODE_TYPE_COLLECTION ||
       type == NODE_TYPE_PARAMETER ||
       type == NODE_TYPE_ATTRIBUTE_ACCESS ||
@@ -107,6 +107,13 @@ void AstNode::toJson (TRI_json_t* json,
       }
     }
   }
+
+  if (type == NODE_TYPE_VARIABLE) {
+    auto variable = static_cast<Variable*>(getData());
+
+    TRI_Insert3ArrayJson(zone, node, "name", TRI_CreateStringCopyJson(zone, variable->name.c_str()));
+    TRI_Insert3ArrayJson(zone, node, "id", TRI_CreateNumberJson(zone, static_cast<double>(variable->id)));
+  }
   
   // dump sub-nodes 
   size_t const n = members._length;
diff --git a/arangod/Aql/AstNode.h b/arangod/Aql/AstNode.h
index 857fab4163..2444175aa3 100644
--- a/arangod/Aql/AstNode.h
+++ b/arangod/Aql/AstNode.h
@@ -61,6 +61,7 @@ namespace triagens {
         double      _double;
         bool        _bool;
         char const* _string;
+        void*       _data;
       } value;
       AstNodeValueType type;
     };
@@ -287,6 +288,22 @@ namespace triagens {
           value.value._string = v;
         }
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief return the data value of a node
+////////////////////////////////////////////////////////////////////////////////
+
+        inline void* getData () const {
+          return value.value._data;
+        }
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief set the data value of a node
+////////////////////////////////////////////////////////////////////////////////
+
+        inline void setData (void* v) {
+          value.value._data = v;
+        }
+
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief return the type name of a node
 ////////////////////////////////////////////////////////////////////////////////
@@ -299,9 +316,12 @@ namespace triagens {
 
       public:
   
-        TRI_vector_pointer_t  members;
         AstNodeType const     type;
         AstNodeValue          value;
+        
+      private:
+      
+        TRI_vector_pointer_t  members;
     };
 
   }
diff --git a/arangod/Aql/ParseResult.h b/arangod/Aql/ParseResult.h
index b79192a1e6..10c8e07b52 100644
--- a/arangod/Aql/ParseResult.h
+++ b/arangod/Aql/ParseResult.h
@@ -41,14 +41,18 @@ namespace triagens {
 // -----------------------------------------------------------------------------
 
     struct ParseResult {
+      ParseResult () = delete;
+
+      ParseResult& operator= (ParseResult const& other) = delete;
+      
       ParseResult (ParseResult&& other) {
+        code = other.code;
+        explanation = other.explanation;
         json = other.json;
         zone = other.zone;
         other.json = nullptr;
       }
 
-      ParseResult& operator= (ParseResult const& other) = delete;
-
       ParseResult (int code,
                    std::string const& explanation) 
         : code(code),
@@ -58,7 +62,9 @@ namespace triagens {
       }
 
       ParseResult (TRI_memory_zone_t* zone) 
-        : zone(zone),
+        : code(TRI_ERROR_NO_ERROR),
+          explanation(),
+          zone(zone),
           json(nullptr) {
       }
 
diff --git a/arangod/Aql/Parser.cpp b/arangod/Aql/Parser.cpp
index 3043a3130e..caa06dae8f 100644
--- a/arangod/Aql/Parser.cpp
+++ b/arangod/Aql/Parser.cpp
@@ -128,6 +128,7 @@ ParseResult Parser::parse () {
     auto error         = _query->error();
     result.code        = error->code;
     result.explanation = error->explanation;
+
     return result;
   }
 
diff --git a/arangod/Aql/QueryAst.cpp b/arangod/Aql/QueryAst.cpp
index 673039aebf..b63d0685de 100644
--- a/arangod/Aql/QueryAst.cpp
+++ b/arangod/Aql/QueryAst.cpp
@@ -103,7 +103,7 @@ TRI_json_t* QueryAst::toJson (TRI_memory_zone_t* zone) {
 void QueryAst::addOperation (AstNode* node) {
   TRI_ASSERT(_root != nullptr);
 
-  TRI_PushBackVectorPointer(&_root->members, (void*) node);
+  _root->addMember(node);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -352,7 +352,8 @@ AstNode* QueryAst::createNodeVariable (char const* name,
   AstNode* node = createNode(NODE_TYPE_VARIABLE);
   node->setStringValue(name);
 
-  _scopes.addVariable(name, isUserDefined);
+  auto variable = _scopes.addVariable(name, isUserDefined);
+  node->setData(static_cast<void*>(variable));
 
   return node;
 }
@@ -666,10 +667,23 @@ void QueryAst::injectBindParameters (BindParameters& parameters) {
       if (*param == '@') {
         // collection parameter
         TRI_ASSERT(TRI_IsStringJson(value));
-       
+
+        bool isWriteCollection = false;
+        if (_writeCollection != nullptr && 
+            _writeCollection->type == NODE_TYPE_PARAMETER &&
+            strcmp(param, _writeCollection->getStringValue()) == 0) {
+          isWriteCollection = true;
+        }
+
         // turn node into a collection node
         char const* name = registerString(value->_value._string.data, value->_value._string.length - 1, false);
+
         node = createNodeCollection(name);
+
+        if (isWriteCollection) {
+          // this was the bind parameter that contained the collection to update 
+          _writeCollection = node;
+        }
       }
       else {
         node = nodeFromJson((*it).second);
diff --git a/arangod/Aql/QueryAst.h b/arangod/Aql/QueryAst.h
index 002f739be3..21de358e28 100644
--- a/arangod/Aql/QueryAst.h
+++ b/arangod/Aql/QueryAst.h
@@ -112,6 +112,7 @@ namespace triagens {
         inline void setWriteCollection (AstNode const* node) {
           TRI_ASSERT(node->type == NODE_TYPE_COLLECTION ||
                      node->type == NODE_TYPE_PARAMETER);
+
           _writeCollection = node;
         }
 
diff --git a/arangod/Aql/Scopes.cpp b/arangod/Aql/Scopes.cpp
index 25763aaf05..8a4a1581e1 100644
--- a/arangod/Aql/Scopes.cpp
+++ b/arangod/Aql/Scopes.cpp
@@ -82,9 +82,9 @@ std::string Scope::typeName () const {
 /// @brief adds a variable to the scope
 ////////////////////////////////////////////////////////////////////////////////
 
-void Scope::addVariable (std::string const& name,
-                         size_t id,
-                         bool isUserDefined) {
+Variable* Scope::addVariable (std::string const& name,
+                              size_t id,
+                              bool isUserDefined) {
   auto variable = new Variable(name, id, isUserDefined);
 
   try {
@@ -94,7 +94,9 @@ void Scope::addVariable (std::string const& name,
     // prevent memleak
     delete variable;
     THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY);
-  }   
+  }  
+  
+  return variable; 
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -198,8 +200,8 @@ void Scopes::endNested () {
 /// @brief adds a variable to the current scope
 ////////////////////////////////////////////////////////////////////////////////
 
-bool Scopes::addVariable (char const* name,
-                          bool isUserDefined) {
+Variable* Scopes::addVariable (char const* name,
+                               bool isUserDefined) {
   TRI_ASSERT(! _activeScopes.empty());
 
   for (auto it = _activeScopes.rbegin(); it != _activeScopes.rend(); ++it) {
@@ -207,12 +209,13 @@ bool Scopes::addVariable (char const* name,
 
     if (scope->existsVariable(name)) {
       // duplicate variable name
-      return false;
+      return 0;
     }
   }
 
-  _activeScopes.back()->addVariable(std::string(name), ++_variableId, isUserDefined);
-  return true;
+  size_t id = ++_variableId;
+
+  return _activeScopes.back()->addVariable(std::string(name), id, isUserDefined);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/arangod/Aql/Scopes.h b/arangod/Aql/Scopes.h
index 10c8c4836d..a7b4381d7e 100644
--- a/arangod/Aql/Scopes.h
+++ b/arangod/Aql/Scopes.h
@@ -35,13 +35,6 @@
 namespace triagens {
   namespace aql {
 
-    template<typename T> 
-    struct CharComparer : public binary_function<T, T, bool> {
-      bool operator () (T const& lhs, T const& rhs) const {
-        return strcmp(lhs, rhs) == 0;
-      }
-    };
-
 // -----------------------------------------------------------------------------
 // --SECTION--                                                   struct Variable
 // -----------------------------------------------------------------------------
@@ -122,9 +115,9 @@ namespace triagens {
 /// @brief adds a variable to the scope
 ////////////////////////////////////////////////////////////////////////////////
 
-        void addVariable (std::string const&,
-                          size_t,
-                          bool);
+        Variable* addVariable (std::string const&,
+                               size_t,
+                               bool);
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief checks if a variable exists in the scope
@@ -207,8 +200,8 @@ namespace triagens {
 /// @brief adds a variable to the current scope
 ////////////////////////////////////////////////////////////////////////////////
 
-        bool addVariable (char const*,
-                          bool);
+        Variable* addVariable (char const*,
+                               bool);
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief checks whether a variable exists in any scope