Add support for defining persistent objects as class template instantiations

1 files changed, 19 insertions, 41 deletions

diff --git a/odb/traits.hxx b/odb/traits.hxx
index 495d972..5dfee3a 100644
--- a/odb/traits.hxx
+++ b/odb/traits.hxx
@@ -12,6 +12,25 @@
 
 namespace odb
 {
+  // Fallback dummy for non-persistent classes. It is necessary to allow
+  // the C++ compiler to instantiate persist(), etc., signatures in class
+  // database when T is a pointer (raw, smart). The overloads that use
+  // these dummy would never actually be selected by the compiler.
+  //
+  template <typename T>
+  class access::object_traits
+  {
+    // If a C++ compiler issues an error pointing to this c;ass and saying
+    // that it missing some declaration, then you are most likely trying to
+    // perform a database operation on a C++ type that is not a persistent
+    // object. Or you forgot to include the corresponding -odb.hxx file.
+    //
+  public:
+    struct id_type {};
+    typedef T object_type;
+    typedef T* pointer_type;
+  };
+
   template <typename T, typename P>
   class access::object_factory
   {
@@ -140,47 +159,6 @@ namespace odb
     static const bool polymorphic = access::object_traits<T>::polymorphic;
   };
 
-  // Specializations for pointer types to allow the C++ compiler to
-  // instantiate persist(), etc., signatures in class database. The
-  // overloads that use these specializations would never actually
-  // be selected by the compiler.
-  //
-  template <typename T>
-  struct object_traits<T*>
-  {
-    struct id_type {};
-  };
-
-  template <typename T>
-  struct object_traits<T* const>
-  {
-    struct id_type {};
-  };
-
-  template <typename T, template <typename> class P>
-  struct object_traits<P<T> >
-  {
-    struct id_type {};
-  };
-
-  template <typename T, typename A1, template <typename, typename> class P>
-  struct object_traits<P<T, A1> >
-  {
-    struct id_type {};
-  };
-
-  template <typename T, template <typename> class P>
-  struct object_traits<const P<T> >
-  {
-    struct id_type {};
-  };
-
-  template <typename T, typename A1, template <typename, typename> class P>
-  struct object_traits<const P<T, A1> >
-  {
-    struct id_type {};
-  };
-
   // Specialization for section to allow instantiation of all the load()
   // signature.
   //