Ground work for multi-database support

All generated code now includes database id. The database-specific
database class interface has been updated to include all the database
operations. The database-specific tests now use this interface.

23 files changed, 894 insertions, 261 deletions

diff --git a/odb/oracle/database.cxx b/odb/oracle/database.cxx
index bb086f6..e71eb40 100644
--- a/odb/oracle/database.cxx
+++ b/odb/oracle/database.cxx
@@ -28,7 +28,8 @@ namespace odb
               ub2 ncharset,
               OCIEnv* environment,
               transfer_ptr<connection_factory> factory)
-        : user_ (user),
+        : odb::database (id_oracle),
+          user_ (user),
           password_ (password),
           db_ (db),
           port_ (0),
@@ -67,7 +68,8 @@ namespace odb
               ub2 ncharset,
               OCIEnv* environment,
               transfer_ptr<connection_factory> factory)
-        : user_ (user),
+        : odb::database (id_oracle),
+          user_ (user),
           password_ (password),
           service_ (service),
           host_ (host),
@@ -125,7 +127,8 @@ namespace odb
               ub2 ncharset,
               OCIEnv* environment,
               transfer_ptr<connection_factory> factory)
-        : port_ (0),
+        : odb::database (id_oracle),
+          port_ (0),
           charset_ (charset),
           ncharset_ (ncharset),
           environment_ (environment),
diff --git a/odb/oracle/database.hxx b/odb/oracle/database.hxx
index b92f00d..da98228 100644
--- a/odb/oracle/database.hxx
+++ b/odb/oracle/database.hxx
@@ -17,6 +17,7 @@
 
 #include <odb/oracle/version.hxx>
 #include <odb/oracle/forward.hxx>
+#include <odb/oracle/query.hxx>
 #include <odb/oracle/tracer.hxx>
 #include <odb/oracle/connection.hxx>
 #include <odb/oracle/connection-factory.hxx>
@@ -82,6 +83,191 @@ namespace odb
       static void
       print_usage (std::ostream&);
 
+      // Object persistence API.
+      //
+    public:
+
+      // Make the object persistent.
+      //
+      template <typename T>
+      typename object_traits<T>::id_type
+      persist (T& object);
+
+      template <typename T>
+      typename object_traits<T>::id_type
+      persist (T* obj_ptr);
+
+      template <typename T, template <typename> class P>
+      typename object_traits<T>::id_type
+      persist (const P<T>& obj_ptr);
+
+      template <typename T, typename A1, template <typename, typename> class P>
+      typename object_traits<T>::id_type
+      persist (const P<T, A1>& obj_ptr);
+
+      template <typename T, template <typename> class P>
+      typename object_traits<T>::id_type
+      persist (P<T>& obj_ptr);
+
+      template <typename T, typename A1, template <typename, typename> class P>
+      typename object_traits<T>::id_type
+      persist (P<T, A1>& obj_ptr);
+
+      template <typename T>
+      typename object_traits<T>::id_type
+      persist (const typename object_traits<T>::pointer_type& obj_ptr);
+
+      // Load an object. Throw object_not_persistent if not found.
+      //
+      template <typename T>
+      typename object_traits<T>::pointer_type
+      load (const typename object_traits<T>::id_type& id);
+
+      template <typename T>
+      void
+      load (const typename object_traits<T>::id_type& id, T& object);
+
+      // Reload an object.
+      //
+      template <typename T>
+      void
+      reload (T& object);
+
+      template <typename T>
+      void
+      reload (T* obj_ptr);
+
+      template <typename T, template <typename> class P>
+      void
+      reload (const P<T>& obj_ptr);
+
+      template <typename T, typename A1, template <typename, typename> class P>
+      void
+      reload (const P<T, A1>& obj_ptr);
+
+      template <typename T, template <typename> class P>
+      void
+      reload (P<T>& obj_ptr);
+
+      template <typename T, typename A1, template <typename, typename> class P>
+      void
+      reload (P<T, A1>& obj_ptr);
+
+      template <typename T>
+      void
+      reload (const typename object_traits<T>::pointer_type& obj_ptr);
+
+      // Loan an object if found. Return NULL/false if not found.
+      //
+      template <typename T>
+      typename object_traits<T>::pointer_type
+      find (const typename object_traits<T>::id_type& id);
+
+      template <typename T>
+      bool
+      find (const typename object_traits<T>::id_type& id, T& object);
+
+      // Update the state of a modified objects.
+      //
+      template <typename T>
+      void
+      update (T& object);
+
+      template <typename T>
+      void
+      update (T* obj_ptr);
+
+      template <typename T, template <typename> class P>
+      void
+      update (const P<T>& obj_ptr);
+
+      template <typename T, typename A1, template <typename, typename> class P>
+      void
+      update (const P<T, A1>& obj_ptr);
+
+      template <typename T, template <typename> class P>
+      void
+      update (P<T>& obj_ptr);
+
+      template <typename T, typename A1, template <typename, typename> class P>
+      void
+      update (P<T, A1>& obj_ptr);
+
+      template <typename T>
+      void
+      update (const typename object_traits<T>::pointer_type& obj_ptr);
+
+      // Make the object transient. Throw object_not_persistent if not
+      // found.
+      //
+      template <typename T>
+      void
+      erase (const typename object_traits<T>::id_type& id);
+
+      template <typename T>
+      void
+      erase (T& object);
+
+      template <typename T>
+      void
+      erase (T* obj_ptr);
+
+      template <typename T, template <typename> class P>
+      void
+      erase (const P<T>& obj_ptr);
+
+      template <typename T, typename A1, template <typename, typename> class P>
+      void
+      erase (const P<T, A1>& obj_ptr);
+
+      template <typename T, template <typename> class P>
+      void
+      erase (P<T>& obj_ptr);
+
+      template <typename T, typename A1, template <typename, typename> class P>
+      void
+      erase (P<T, A1>& obj_ptr);
+
+      template <typename T>
+      void
+      erase (const typename object_traits<T>::pointer_type& obj_ptr);
+
+      // Erase multiple objects matching a query predicate.
+      //
+      template <typename T>
+      unsigned long long
+      erase_query ();
+
+      template <typename T>
+      unsigned long long
+      erase_query (const char*);
+
+      template <typename T>
+      unsigned long long
+      erase_query (const std::string&);
+
+      template <typename T>
+      unsigned long long
+      erase_query (const oracle::query<T>&);
+
+      // Query API.
+      //
+      template <typename T>
+      result<T>
+      query ();
+
+      template <typename T>
+      result<T>
+      query (const char*);
+
+      template <typename T>
+      result<T>
+      query (const std::string&);
+
+      template <typename T>
+      result<T>
+      query (const oracle::query<T>&);
+
     public:
       virtual transaction_impl*
       begin ();
diff --git a/odb/oracle/database.ixx b/odb/oracle/database.ixx
index be4c748..6d60d1e 100644
--- a/odb/oracle/database.ixx
+++ b/odb/oracle/database.ixx
@@ -15,5 +15,383 @@ namespace odb
       return connection_ptr (
         static_cast<oracle::connection*> (connection_ ()));
     }
+
+    template <typename T>
+    inline typename object_traits<T>::id_type database::
+    persist (T& obj)
+    {
+      return persist_<T, id_oracle> (obj);
+    }
+
+    template <typename T>
+    inline typename object_traits<T>::id_type database::
+    persist (T* p)
+    {
+      typedef typename object_traits<T>::pointer_type object_pointer;
+
+      // The passed pointer should be the same or implicit-convertible
+      // to the object pointer. This way we make sure the object pointer
+      // does not assume ownership of the passed object.
+      //
+      const object_pointer& pobj (p);
+
+      return persist_<T, id_oracle> (pobj);
+    }
+
+    template <typename T, template <typename> class P>
+    inline typename object_traits<T>::id_type database::
+    persist (const P<T>& p)
+    {
+      typedef typename object_traits<T>::pointer_type object_pointer;
+
+      // The passed pointer should be the same or implicit-convertible
+      // to the object pointer. This way we make sure the object pointer
+      // does not assume ownership of the passed object.
+      //
+      const object_pointer& pobj (p);
+
+      return persist_<T, id_oracle> (pobj);
+    }
+
+    template <typename T, typename A1, template <typename, typename> class P>
+    inline typename object_traits<T>::id_type database::
+    persist (const P<T, A1>& p)
+    {
+      typedef typename object_traits<T>::pointer_type object_pointer;
+
+      // The passed pointer should be the same or implicit-convertible
+      // to the object pointer. This way we make sure the object pointer
+      // does not assume ownership of the passed object.
+      //
+      const object_pointer& pobj (p);
+
+      return persist_<T, id_oracle> (pobj);
+    }
+
+    template <typename T, template <typename> class P>
+    inline typename object_traits<T>::id_type database::
+    persist (P<T>& p)
+    {
+      const P<T>& cr (p);
+      return persist<T, P> (cr);
+    }
+
+    template <typename T, typename A1, template <typename, typename> class P>
+    inline typename object_traits<T>::id_type database::
+    persist (P<T, A1>& p)
+    {
+      const P<T, A1>& cr (p);
+      return persist<T, A1, P> (cr);
+    }
+
+    template <typename T>
+    inline typename object_traits<T>::id_type database::
+    persist (const typename object_traits<T>::pointer_type& pobj)
+    {
+      return persist_<T, id_oracle> (pobj);
+    }
+
+    template <typename T>
+    inline typename object_traits<T>::pointer_type database::
+    load (const typename object_traits<T>::id_type& id)
+    {
+      return load_<T, id_oracle> (id);
+    }
+
+    template <typename T>
+    inline void database::
+    load (const typename object_traits<T>::id_type& id, T& obj)
+    {
+      return load_<T, id_oracle> (id, obj);
+    }
+
+    template <typename T>
+    inline typename object_traits<T>::pointer_type database::
+    find (const typename object_traits<T>::id_type& id)
+    {
+      return find_<T, id_oracle> (id);
+    }
+
+    template <typename T>
+    inline bool database::
+    find (const typename object_traits<T>::id_type& id, T& obj)
+    {
+      return find_<T, id_oracle> (id, obj);
+    }
+
+    template <typename T>
+    inline void database::
+    reload (T& obj)
+    {
+      reload_<T, id_oracle> (obj);
+    }
+
+    template <typename T>
+    inline void database::
+    reload (T* p)
+    {
+      reload<T> (*p);
+    }
+
+    template <typename T, template <typename> class P>
+    inline void database::
+    reload (const P<T>& p)
+    {
+      reload (odb::pointer_traits< P<T> >::get_ref (p));
+    }
+
+    template <typename T, typename A1, template <typename, typename> class P>
+    inline void database::
+    reload (const P<T, A1>& p)
+    {
+      reload (odb::pointer_traits< P<T, A1> >::get_ref (p));
+    }
+
+    template <typename T, template <typename> class P>
+    inline void database::
+    reload (P<T>& p)
+    {
+      reload (odb::pointer_traits< P<T> >::get_ref (p));
+    }
+
+    template <typename T, typename A1, template <typename, typename> class P>
+    inline void database::
+    reload (P<T, A1>& p)
+    {
+      reload (odb::pointer_traits< P<T, A1> >::get_ref (p));
+    }
+
+    template <typename T>
+    inline void database::
+    reload (const typename object_traits<T>::pointer_type& pobj)
+    {
+      typedef typename object_traits<T>::pointer_type pointer_type;
+
+      reload (odb::pointer_traits<pointer_type>::get_ref (pobj));
+    }
+
+    template <typename T>
+    inline void database::
+    update (T& obj)
+    {
+      update_<T, id_oracle> (obj);
+    }
+
+    template <typename T>
+    inline void database::
+    update (T* p)
+    {
+      typedef typename object_traits<T>::pointer_type object_pointer;
+
+      // The passed pointer should be the same or implicit-convertible
+      // to the object pointer. This way we make sure the object pointer
+      // does not assume ownership of the passed object.
+      //
+      const object_pointer& pobj (p);
+
+      update_<T, id_oracle> (pobj);
+    }
+
+    template <typename T, template <typename> class P>
+    inline void database::
+    update (const P<T>& p)
+    {
+      typedef typename object_traits<T>::pointer_type object_pointer;
+
+      // The passed pointer should be the same or implicit-convertible
+      // to the object pointer. This way we make sure the object pointer
+      // does not assume ownership of the passed object.
+      //
+      const object_pointer& pobj (p);
+
+      update_<T, id_oracle> (pobj);
+    }
+
+    template <typename T, typename A1, template <typename, typename> class P>
+    inline void database::
+    update (const P<T, A1>& p)
+    {
+      typedef typename object_traits<T>::pointer_type object_pointer;
+
+      // The passed pointer should be the same or implicit-convertible
+      // to the object pointer. This way we make sure the object pointer
+      // does not assume ownership of the passed object.
+      //
+      const object_pointer& pobj (p);
+
+      update_<T, id_oracle> (pobj);
+    }
+
+    template <typename T, template <typename> class P>
+    inline void database::
+    update (P<T>& p)
+    {
+      const P<T>& cr (p);
+      update<T, P> (cr);
+    }
+
+    template <typename T, typename A1, template <typename, typename> class P>
+    inline void database::
+    update (P<T, A1>& p)
+    {
+      const P<T, A1>& cr (p);
+      update<T, A1, P> (cr);
+    }
+
+    template <typename T>
+    inline void database::
+    update (const typename object_traits<T>::pointer_type& pobj)
+    {
+      update_<T, id_oracle> (pobj);
+    }
+
+    template <typename T>
+    inline void database::
+    erase (const typename object_traits<T>::id_type& id)
+    {
+      return erase_<T, id_oracle> (id);
+    }
+
+    template <typename T>
+    inline void database::
+    erase (T& obj)
+    {
+      return erase_<T, id_oracle> (obj);
+    }
+
+    template <typename T>
+    inline void database::
+    erase (T* p)
+    {
+      typedef typename object_traits<T>::pointer_type object_pointer;
+
+      // The passed pointer should be the same or implicit-convertible
+      // to the object pointer. This way we make sure the object pointer
+      // does not assume ownership of the passed object.
+      //
+      const object_pointer& pobj (p);
+
+      erase_<T, id_oracle> (pobj);
+    }
+
+    template <typename T, template <typename> class P>
+    inline void database::
+    erase (const P<T>& p)
+    {
+      typedef typename object_traits<T>::pointer_type object_pointer;
+
+      // The passed pointer should be the same or implicit-convertible
+      // to the object pointer. This way we make sure the object pointer
+      // does not assume ownership of the passed object.
+      //
+      const object_pointer& pobj (p);
+
+      erase_<T, id_oracle> (pobj);
+    }
+
+    template <typename T, typename A1, template <typename, typename> class P>
+    inline void database::
+    erase (const P<T, A1>& p)
+    {
+      typedef typename object_traits<T>::pointer_type object_pointer;
+
+      // The passed pointer should be the same or implicit-convertible
+      // to the object pointer. This way we make sure the object pointer
+      // does not assume ownership of the passed object.
+      //
+      const object_pointer& pobj (p);
+
+      erase_<T, id_oracle> (pobj);
+    }
+
+    template <typename T, template <typename> class P>
+    inline void database::
+    erase (P<T>& p)
+    {
+      const P<T>& cr (p);
+      erase<T, P> (cr);
+    }
+
+    template <typename T, typename A1, template <typename, typename> class P>
+    inline void database::
+    erase (P<T, A1>& p)
+    {
+      const P<T, A1>& cr (p);
+      erase<T, A1, P> (cr);
+    }
+
+    template <typename T>
+    inline void database::
+    erase (const typename object_traits<T>::pointer_type& pobj)
+    {
+      erase_<T, id_oracle> (pobj);
+    }
+
+    template <typename T>
+    inline unsigned long long database::
+    erase_query ()
+    {
+      // T is always object_type.
+      //
+      return erase_query<T> (oracle::query<T> ());
+    }
+
+    template <typename T>
+    inline unsigned long long database::
+    erase_query (const char* q)
+    {
+      // T is always object_type.
+      //
+      return erase_query<T> (oracle::query<T> (q));
+    }
+
+    template <typename T>
+    inline unsigned long long database::
+    erase_query (const std::string& q)
+    {
+      // T is always object_type.
+      //
+      return erase_query<T> (oracle::query<T> (q));
+    }
+
+    template <typename T>
+    inline unsigned long long database::
+    erase_query (const oracle::query<T>& q)
+    {
+      // T is always object_type.
+      //
+      return object_traits_impl<T, id_oracle>::erase_query (*this, q);
+    }
+
+    template <typename T>
+    inline result<T> database::
+    query ()
+    {
+      return query<T> (oracle::query<T> ());
+    }
+
+    template <typename T>
+    inline result<T> database::
+    query (const char* q)
+    {
+      return query<T> (oracle::query<T> (q));
+    }
+
+    template <typename T>
+    inline result<T> database::
+    query (const std::string& q)
+    {
+      return query<T> (oracle::query<T> (q));
+    }
+
+    template <typename T>
+    inline result<T> database::
+    query (const oracle::query<T>& q)
+    {
+      // T is always object_type. We also don't need to check for transaction
+      // here; object_traits::query () does this.
+      //
+      return query_<T, id_oracle>::call (*this, q);
+    }
   }
 }
diff --git a/odb/oracle/forward.hxx b/odb/oracle/forward.hxx
index 484fbfc..24dbf44 100644
--- a/odb/oracle/forward.hxx
+++ b/odb/oracle/forward.hxx
@@ -20,7 +20,6 @@ namespace odb
     class statement;
     class transaction;
     class tracer;
-    class query;
 
     // Implementation details.
     //
@@ -51,6 +50,8 @@ namespace odb
 
     template <typename T>
     class container_statements;
+
+    class query_base;
   }
 
   namespace details
diff --git a/odb/oracle/no-id-object-result.hxx b/odb/oracle/no-id-object-result.hxx
index bd00b15..499c1b6 100644
--- a/odb/oracle/no-id-object-result.hxx
+++ b/odb/oracle/no-id-object-result.hxx
@@ -14,7 +14,7 @@
 #include <odb/details/shared-ptr.hxx>
 
 #include <odb/oracle/version.hxx>
-#include <odb/oracle/forward.hxx> // query
+#include <odb/oracle/forward.hxx> // query_base
 #include <odb/oracle/statement.hxx>
 
 namespace odb
@@ -28,9 +28,9 @@ namespace odb
       typedef odb::no_id_object_result_impl<T> base_type;
 
       typedef typename base_type::object_type object_type;
-      typedef typename base_type::object_traits object_traits;
-
       typedef typename base_type::pointer_type pointer_type;
+
+      typedef object_traits_impl<object_type, id_oracle> object_traits;
       typedef typename base_type::pointer_traits pointer_traits;
 
       typedef typename object_traits::statements_type statements_type;
@@ -38,7 +38,7 @@ namespace odb
       virtual
       ~no_id_object_result_impl ();
 
-      no_id_object_result_impl (const query&,
+      no_id_object_result_impl (const query_base&,
                                 details::shared_ptr<select_statement>,
                                 statements_type&);
 
diff --git a/odb/oracle/no-id-object-result.txx b/odb/oracle/no-id-object-result.txx
index 3d1f63b..405d139 100644
--- a/odb/oracle/no-id-object-result.txx
+++ b/odb/oracle/no-id-object-result.txx
@@ -31,7 +31,7 @@ namespace odb
 
     template <typename T>
     no_id_object_result_impl<T>::
-    no_id_object_result_impl (const query&,
+    no_id_object_result_impl (const query_base&,
                               details::shared_ptr<select_statement> statement,
                               statements_type& statements)
         : base_type (statements.connection ().database ()),
diff --git a/odb/oracle/no-id-object-statements.hxx b/odb/oracle/no-id-object-statements.hxx
index 0aa5cf0..613da39 100644
--- a/odb/oracle/no-id-object-statements.hxx
+++ b/odb/oracle/no-id-object-statements.hxx
@@ -34,7 +34,7 @@ namespace odb
     {
     public:
       typedef T object_type;
-      typedef odb::object_traits<object_type> object_traits;
+      typedef object_traits_impl<object_type, id_oracle> object_traits;
       typedef typename object_traits::pointer_type pointer_type;
       typedef typename object_traits::image_type image_type;
 
diff --git a/odb/oracle/polymorphic-object-result.hxx b/odb/oracle/polymorphic-object-result.hxx
index 2137c1d..5092aa7 100644
--- a/odb/oracle/polymorphic-object-result.hxx
+++ b/odb/oracle/polymorphic-object-result.hxx
@@ -14,7 +14,7 @@
 #include <odb/details/shared-ptr.hxx>
 
 #include <odb/oracle/version.hxx>
-#include <odb/oracle/forward.hxx> // query
+#include <odb/oracle/forward.hxx> // query_base
 #include <odb/oracle/statement.hxx>
 
 namespace odb
@@ -28,24 +28,25 @@ namespace odb
     public:
       typedef odb::polymorphic_object_result_impl<T> base_type;
 
-      typedef typename base_type::object_type object_type;
-      typedef typename base_type::object_traits object_traits;
       typedef typename base_type::id_type id_type;
-
+      typedef typename base_type::object_type object_type;
       typedef typename base_type::pointer_type pointer_type;
+
+      typedef object_traits_impl<object_type, id_oracle> object_traits;
       typedef typename base_type::pointer_traits pointer_traits;
 
       typedef typename base_type::root_type root_type;
-      typedef typename base_type::root_traits root_traits;
       typedef typename base_type::discriminator_type discriminator_type;
 
+      typedef object_traits_impl<root_type, id_oracle> root_traits;
+
       typedef typename object_traits::image_type image_type;
       typedef typename object_traits::statements_type statements_type;
 
       virtual
       ~polymorphic_object_result_impl ();
 
-      polymorphic_object_result_impl (const query&,
+      polymorphic_object_result_impl (const query_base&,
                                       details::shared_ptr<select_statement>,
                                       statements_type&);
 
diff --git a/odb/oracle/polymorphic-object-result.txx b/odb/oracle/polymorphic-object-result.txx
index af9f8eb..9db06cc 100644
--- a/odb/oracle/polymorphic-object-result.txx
+++ b/odb/oracle/polymorphic-object-result.txx
@@ -35,7 +35,7 @@ namespace odb
 
     template <typename T>
     polymorphic_object_result_impl<T>::
-    polymorphic_object_result_impl (const query&,
+    polymorphic_object_result_impl (const query_base&,
                                     details::shared_ptr<select_statement> st,
                                     statements_type& sts)
         : base_type (sts.connection ().database ()),
@@ -191,7 +191,7 @@ namespace odb
     {
       // Derived type version.
       //
-      typedef object_traits<T> traits;
+      typedef object_traits_impl<T, id_oracle> traits;
 
       static void
       rebind (typename traits::statements_type& sts)
@@ -223,7 +223,7 @@ namespace odb
     {
       // Root type version.
       //
-      typedef object_traits<R> traits;
+      typedef object_traits_impl<R, id_oracle> traits;
 
       static void
       rebind (typename traits::statements_type& sts)
diff --git a/odb/oracle/polymorphic-object-statements.hxx b/odb/oracle/polymorphic-object-statements.hxx
index dce30c3..88ed575 100644
--- a/odb/oracle/polymorphic-object-statements.hxx
+++ b/odb/oracle/polymorphic-object-statements.hxx
@@ -148,7 +148,7 @@ namespace odb
     {
     public:
       typedef T object_type;
-      typedef odb::object_traits<object_type> object_traits;
+      typedef object_traits_impl<object_type, id_oracle> object_traits;
       typedef typename object_traits::id_type id_type;
       typedef typename object_traits::pointer_type pointer_type;
       typedef typename object_traits::id_image_type id_image_type;
diff --git a/odb/oracle/query-const-expr.cxx b/odb/oracle/query-const-expr.cxx
index 33b41bc..c11f677 100644
--- a/odb/oracle/query-const-expr.cxx
+++ b/odb/oracle/query-const-expr.cxx
@@ -10,6 +10,6 @@ namespace odb
   {
     // Sun CC cannot handle this in query.cxx.
     //
-    const query query::true_expr (true);
+    const query_base query_base::true_expr (true);
   }
 }
diff --git a/odb/oracle/query.cxx b/odb/oracle/query.cxx
index e66d9e4..df6a629 100644
--- a/odb/oracle/query.cxx
+++ b/odb/oracle/query.cxx
@@ -21,10 +21,10 @@ namespace odb
     {
     }
 
-    // query
+    // query_base
     //
-    query::
-    query (const query& q)
+    query_base::
+    query_base (const query_base& q)
         : clause_ (q.clause_),
           parameters_ (q.parameters_),
           bind_ (q.bind_),
@@ -44,8 +44,8 @@ namespace odb
       }
     }
 
-    query& query::
-    operator= (const query& q)
+    query_base& query_base::
+    operator= (const query_base& q)
     {
       if (this != &q)
       {
@@ -62,8 +62,8 @@ namespace odb
       return *this;
     }
 
-    query& query::
-    operator+= (const query& q)
+    query_base& query_base::
+    operator+= (const query_base& q)
     {
       clause_.insert (clause_.end (), q.clause_.begin (), q.clause_.end ());
 
@@ -85,7 +85,7 @@ namespace odb
       return *this;
     }
 
-    void query::
+    void query_base::
     append (const string& q)
     {
       if (!clause_.empty () && clause_.back ().kind == clause_part::native)
@@ -108,7 +108,7 @@ namespace odb
         clause_.push_back (clause_part (clause_part::native, q));
     }
 
-    void query::
+    void query_base::
     append (const char* table, const char* column)
     {
       string s (table);
@@ -118,7 +118,7 @@ namespace odb
       clause_.push_back (clause_part (clause_part::column, s));
     }
 
-    void query::
+    void query_base::
     add (details::shared_ptr<query_param> p, const char* conv)
     {
       clause_.push_back (clause_part (clause_part::param));
@@ -137,7 +137,7 @@ namespace odb
       p->bind (b);
     }
 
-    binding& query::
+    binding& query_base::
     parameters_binding () const
     {
       size_t n (parameters_.size ());
@@ -199,7 +199,7 @@ namespace odb
       return false;
     }
 
-    void query::
+    void query_base::
     optimize ()
     {
       // Remove a single TRUE literal or one that is followe by one of
@@ -219,7 +219,7 @@ namespace odb
       }
     }
 
-    const char* query::
+    const char* query_base::
     clause_prefix () const
     {
       if (!clause_.empty ())
@@ -235,7 +235,7 @@ namespace odb
       return "";
     }
 
-    string query::
+    string query_base::
     clause () const
     {
       string r;
@@ -316,8 +316,8 @@ namespace odb
       return clause_prefix () + r;
     }
 
-    query
-    operator&& (const query& x, const query& y)
+    query_base
+    operator&& (const query_base& x, const query_base& y)
     {
       // Optimize cases where one or both sides are constant truth.
       //
@@ -332,7 +332,7 @@ namespace odb
       if (yt)
         return x;
 
-      query r ("(");
+      query_base r ("(");
       r += x;
       r += ") AND (";
       r += y;
@@ -340,10 +340,10 @@ namespace odb
       return r;
     }
 
-    query
-    operator|| (const query& x, const query& y)
+    query_base
+    operator|| (const query_base& x, const query_base& y)
     {
-      query r ("(");
+      query_base r ("(");
       r += x;
       r += ") OR (";
       r += y;
@@ -351,10 +351,10 @@ namespace odb
       return r;
     }
 
-    query
-    operator! (const query& x)
+    query_base
+    operator! (const query_base& x)
     {
-      query r ("NOT (");
+      query_base r ("NOT (");
       r += x;
       r += ")";
       return r;
diff --git a/odb/oracle/query.hxx b/odb/oracle/query.hxx
index d6e5a6c..aaba740 100644
--- a/odb/oracle/query.hxx
+++ b/odb/oracle/query.hxx
@@ -103,7 +103,7 @@ namespace odb
     template <typename T, database_type_id ID>
     struct query_column;
 
-    class LIBODB_ORACLE_EXPORT query
+    class LIBODB_ORACLE_EXPORT query_base
     {
     public:
       struct clause_part
@@ -125,7 +125,7 @@ namespace odb
         bool bool_part;
       };
 
-      query ()
+      query_base ()
         : binding_ (0, 0)
       {
       }
@@ -133,27 +133,27 @@ namespace odb
       // True or false literal.
       //
       explicit
-      query (bool v)
+      query_base (bool v)
         : binding_ (0, 0)
       {
         clause_.push_back (clause_part (v));
       }
 
       explicit
-      query (const char* native)
+      query_base (const char* native)
         : binding_ (0, 0)
       {
         clause_.push_back (clause_part (clause_part::native, native));
       }
 
       explicit
-      query (const std::string& native)
+      query_base (const std::string& native)
         : binding_ (0, 0)
       {
         clause_.push_back (clause_part (clause_part::native, native));
       }
 
-      query (const char* table, const char* column)
+      query_base (const char* table, const char* column)
         : binding_ (0, 0)
       {
         append (table, column);
@@ -161,7 +161,7 @@ namespace odb
 
       template <typename T>
       explicit
-      query (val_bind<T> v)
+      query_base (val_bind<T> v)
         : binding_ (0, 0)
       {
         append<T, type_traits<T>::db_type_id> (
@@ -170,7 +170,7 @@ namespace odb
 
       template <typename T>
       explicit
-      query (ref_bind<T> r)
+      query_base (ref_bind<T> r)
         : binding_ (0, 0)
       {
         append<T, type_traits<T>::db_type_id> (
@@ -178,12 +178,12 @@ namespace odb
       }
 
       template <database_type_id ID>
-      query (const query_column<bool, ID>&);
+      query_base (const query_column<bool, ID>&);
 
-      query (const query&);
+      query_base (const query_base&);
 
-      query&
-      operator= (const query&);
+      query_base&
+      operator= (const query_base&);
 
     public:
       std::string
@@ -202,7 +202,7 @@ namespace odb
         return clause_.empty ();
       }
 
-      static const query true_expr;
+      static const query_base true_expr;
 
       bool
       const_true () const
@@ -231,10 +231,10 @@ namespace odb
       }
 
     public:
-      query&
-      operator+= (const query&);
+      query_base&
+      operator+= (const query_base&);
 
-      query&
+      query_base&
       operator+= (const std::string& q)
       {
         append (q);
@@ -242,7 +242,7 @@ namespace odb
       }
 
       template <typename T>
-      query&
+      query_base&
       operator+= (val_bind<T> v)
       {
         append<T, type_traits<T>::db_type_id> (
@@ -251,7 +251,7 @@ namespace odb
       }
 
       template <typename T>
-      query&
+      query_base&
       operator+= (ref_bind<T> r)
       {
         append<T, type_traits<T>::db_type_id> (
@@ -288,114 +288,114 @@ namespace odb
       mutable binding binding_;
     };
 
-    inline query
-    operator+ (const query& x, const query& y)
+    inline query_base
+    operator+ (const query_base& x, const query_base& y)
     {
-      query r (x);
+      query_base r (x);
       r += y;
       return r;
     }
 
     template <typename T>
-    inline query
-    operator+ (const query& q, val_bind<T> b)
+    inline query_base
+    operator+ (const query_base& q, val_bind<T> b)
     {
-      query r (q);
+      query_base r (q);
       r += b;
       return r;
     }
 
     template <typename T>
-    inline query
-    operator+ (const query& q, ref_bind<T> b)
+    inline query_base
+    operator+ (const query_base& q, ref_bind<T> b)
     {
-      query r (q);
+      query_base r (q);
       r += b;
       return r;
     }
 
     template <typename T>
-    inline query
-    operator+ (val_bind<T> b, const query& q)
+    inline query_base
+    operator+ (val_bind<T> b, const query_base& q)
     {
-      query r;
+      query_base r;
       r += b;
       r += q;
       return r;
     }
 
     template <typename T>
-    inline query
-    operator+ (ref_bind<T> b, const query& q)
+    inline query_base
+    operator+ (ref_bind<T> b, const query_base& q)
     {
-      query r;
+      query_base r;
       r += b;
       r += q;
       return r;
     }
 
-    inline query
-    operator+ (const query& q, const std::string& s)
+    inline query_base
+    operator+ (const query_base& q, const std::string& s)
     {
-      query r (q);
+      query_base r (q);
       r += s;
       return r;
     }
 
-    inline query
-    operator+ (const std::string& s, const query& q)
+    inline query_base
+    operator+ (const std::string& s, const query_base& q)
     {
-      query r (s);
+      query_base r (s);
       r += q;
       return r;
     }
 
     template <typename T>
-    inline query
+    inline query_base
     operator+ (const std::string& s, val_bind<T> b)
     {
-      query r (s);
+      query_base r (s);
       r += b;
       return r;
     }
 
     template <typename T>
-    inline query
+    inline query_base
     operator+ (const std::string& s, ref_bind<T> b)
     {
-      query r (s);
+      query_base r (s);
       r += b;
       return r;
     }
 
     template <typename T>
-    inline query
+    inline query_base
     operator+ (val_bind<T> b, const std::string& s)
     {
-      query r;
+      query_base r;
       r += b;
       r += s;
       return r;
     }
 
     template <typename T>
-    inline query
+    inline query_base
     operator+ (ref_bind<T> b, const std::string& s)
     {
-      query r;
+      query_base r;
       r += b;
       r += s;
       return r;
     }
 
-    LIBODB_ORACLE_EXPORT query
-    operator&& (const query& x, const query& y);
+    LIBODB_ORACLE_EXPORT query_base
+    operator&& (const query_base& x, const query_base& y);
 
-    LIBODB_ORACLE_EXPORT query
-    operator|| (const query& x, const query& y);
+    LIBODB_ORACLE_EXPORT query_base
+    operator|| (const query_base& x, const query_base& y);
 
-    LIBODB_ORACLE_EXPORT query
-    operator! (const query& x);
+    LIBODB_ORACLE_EXPORT query_base
+    operator! (const query_base& x);
 
     // query_column
     //
@@ -465,18 +465,18 @@ namespace odb
       // is_null, is_not_null
       //
     public:
-      query
+      query_base
       is_null () const
       {
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "IS NULL";
         return q;
       }
 
-      query
+      query_base
       is_not_null () const
       {
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "IS NOT NULL";
         return q;
       }
@@ -484,108 +484,108 @@ namespace odb
       // in
       //
     public:
-      query
+      query_base
       in (const T&, const T&) const;
 
-      query
+      query_base
       in (const T&, const T&, const T&) const;
 
-      query
+      query_base
       in (const T&, const T&, const T&, const T&) const;
 
-      query
+      query_base
       in (const T&, const T&, const T&, const T&, const T&) const;
 
       template <typename I>
-      query
+      query_base
       in_range (I begin, I end) const;
 
       // =
       //
     public:
-      query
+      query_base
       equal (const T& v) const
       {
         return equal (val_bind<T> (v));
       }
 
-      query
+      query_base
       equal (val_bind<T> v) const
       {
         v.prec = prec_;
         v.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "=";
         q.append<T, ID> (v, conversion_);
         return q;
       }
 
       template <typename T2>
-      query
+      query_base
       equal (val_bind<T2> v) const
       {
         copy_bind<T, T2> c (v.val);
         return equal (c);
       }
 
-      query
+      query_base
       equal (ref_bind<T> r) const
       {
         r.prec = prec_;
         r.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "=";
         q.append<T, ID> (r, conversion_);
         return q;
       }
 
-      friend query
+      friend query_base
       operator== (const query_column& c, const T& v)
       {
         return c.equal (v);
       }
 
-      friend query
+      friend query_base
       operator== (const T& v, const query_column& c)
       {
         return c.equal (v);
       }
 
-      friend query
+      friend query_base
       operator== (const query_column& c, val_bind<T> v)
       {
         return c.equal (v);
       }
 
-      friend query
+      friend query_base
       operator== (val_bind<T> v, const query_column& c)
       {
         return c.equal (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator== (const query_column& c, val_bind<T2> v)
       {
         return c.equal (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator== (val_bind<T2> v, const query_column& c)
       {
         return c.equal (v);
       }
 
-      friend query
+      friend query_base
       operator== (const query_column& c, ref_bind<T> r)
       {
         return c.equal (r);
       }
 
-      friend query
+      friend query_base
       operator== (ref_bind<T> r, const query_column& c)
       {
         return c.equal (r);
@@ -594,89 +594,89 @@ namespace odb
       // !=
       //
     public:
-      query
+      query_base
       unequal (const T& v) const
       {
         return unequal (val_bind<T> (v));
       }
 
-      query
+      query_base
       unequal (val_bind<T> v) const
       {
         v.prec = prec_;
         v.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "!=";
         q.append<T, ID> (v, conversion_);
         return q;
       }
 
       template <typename T2>
-      query
+      query_base
       unequal (val_bind<T2> v) const
       {
         copy_bind<T, T2> c (v.val);
         return unequal (c);
       }
 
-      query
+      query_base
       unequal (ref_bind<T> r) const
       {
         r.prec = prec_;
         r.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "!=";
         q.append<T, ID> (r, conversion_);
         return q;
       }
 
-      friend query
+      friend query_base
       operator!= (const query_column& c, const T& v)
       {
         return c.unequal (v);
       }
 
-      friend query
+      friend query_base
       operator!= (const T& v, const query_column& c)
       {
         return c.unequal (v);
       }
 
-      friend query
+      friend query_base
       operator!= (const query_column& c, val_bind<T> v)
       {
         return c.unequal (v);
       }
 
-      friend query
+      friend query_base
       operator!= (val_bind<T> v, const query_column& c)
       {
         return c.unequal (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator!= (const query_column& c, val_bind<T2> v)
       {
         return c.unequal (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator!= (val_bind<T2> v, const query_column& c)
       {
         return c.unequal (v);
       }
 
-      friend query
+      friend query_base
       operator!= (const query_column& c, ref_bind<T> r)
       {
         return c.unequal (r);
       }
 
-      friend query
+      friend query_base
       operator!= (ref_bind<T> r, const query_column& c)
       {
         return c.unequal (r);
@@ -685,89 +685,89 @@ namespace odb
       // <
       //
     public:
-      query
+      query_base
       less (const T& v) const
       {
         return less (val_bind<T> (v));
       }
 
-      query
+      query_base
       less (val_bind<T> v) const
       {
         v.prec = prec_;
         v.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "<";
         q.append<T, ID> (v, conversion_);
         return q;
       }
 
       template <typename T2>
-      query
+      query_base
       less (val_bind<T2> v) const
       {
         copy_bind<T, T2> c (v.val);
         return less (c);
       }
 
-      query
+      query_base
       less (ref_bind<T> r) const
       {
         r.prec = prec_;
         r.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "<";
         q.append<T, ID> (r, conversion_);
         return q;
       }
 
-      friend query
+      friend query_base
       operator< (const query_column& c, const T& v)
       {
         return c.less (v);
       }
 
-      friend query
+      friend query_base
       operator< (const T& v, const query_column& c)
       {
         return c.greater (v);
       }
 
-      friend query
+      friend query_base
       operator< (const query_column& c, val_bind<T> v)
       {
         return c.less (v);
       }
 
-      friend query
+      friend query_base
       operator< (val_bind<T> v, const query_column& c)
       {
         return c.greater (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator< (const query_column& c, val_bind<T2> v)
       {
         return c.less (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator< (val_bind<T2> v, const query_column& c)
       {
         return c.greater (v);
       }
 
-      friend query
+      friend query_base
       operator< (const query_column& c, ref_bind<T> r)
       {
         return c.less (r);
       }
 
-      friend query
+      friend query_base
       operator< (ref_bind<T> r, const query_column& c)
       {
         return c.greater (r);
@@ -776,89 +776,89 @@ namespace odb
       // >
       //
     public:
-      query
+      query_base
       greater (const T& v) const
       {
         return greater (val_bind<T> (v));
       }
 
-      query
+      query_base
       greater (val_bind<T> v) const
       {
         v.prec = prec_;
         v.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += ">";
         q.append<T, ID> (v, conversion_);
         return q;
       }
 
       template <typename T2>
-      query
+      query_base
       greater (val_bind<T2> v) const
       {
         copy_bind<T, T2> c (v.val);
         return greater (c);
       }
 
-      query
+      query_base
       greater (ref_bind<T> r) const
       {
         r.prec = prec_;
         r.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += ">";
         q.append<T, ID> (r, conversion_);
         return q;
       }
 
-      friend query
+      friend query_base
       operator> (const query_column& c, const T& v)
       {
         return c.greater (v);
       }
 
-      friend query
+      friend query_base
       operator> (const T& v, const query_column& c)
       {
         return c.less (v);
       }
 
-      friend query
+      friend query_base
       operator> (const query_column& c, val_bind<T> v)
       {
         return c.greater (v);
       }
 
-      friend query
+      friend query_base
       operator> (val_bind<T> v, const query_column& c)
       {
         return c.less (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator> (const query_column& c, val_bind<T2> v)
       {
         return c.greater (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator> (val_bind<T2> v, const query_column& c)
       {
         return c.less (v);
       }
 
-      friend query
+      friend query_base
       operator> (const query_column& c, ref_bind<T> r)
       {
         return c.greater (r);
       }
 
-      friend query
+      friend query_base
       operator> (ref_bind<T> r, const query_column& c)
       {
         return c.less (r);
@@ -867,89 +867,89 @@ namespace odb
       // <=
       //
     public:
-      query
+      query_base
       less_equal (const T& v) const
       {
         return less_equal (val_bind<T> (v));
       }
 
-      query
+      query_base
       less_equal (val_bind<T> v) const
       {
         v.prec = prec_;
         v.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "<=";
         q.append<T, ID> (v, conversion_);
         return q;
       }
 
       template <typename T2>
-      query
+      query_base
       less_equal (val_bind<T2> v) const
       {
         copy_bind<T, T2> c (v.val);
         return less_equal (c);
       }
 
-      query
+      query_base
       less_equal (ref_bind<T> r) const
       {
         r.prec = prec_;
         r.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "<=";
         q.append<T, ID> (r, conversion_);
         return q;
       }
 
-      friend query
+      friend query_base
       operator<= (const query_column& c, const T& v)
       {
         return c.less_equal (v);
       }
 
-      friend query
+      friend query_base
       operator<= (const T& v, const query_column& c)
       {
         return c.greater_equal (v);
       }
 
-      friend query
+      friend query_base
       operator<= (const query_column& c, val_bind<T> v)
       {
         return c.less_equal (v);
       }
 
-      friend query
+      friend query_base
       operator<= (val_bind<T> v, const query_column& c)
       {
         return c.greater_equal (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator<= (const query_column& c, val_bind<T2> v)
       {
         return c.less_equal (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator<= (val_bind<T2> v, const query_column& c)
       {
         return c.greater_equal (v);
       }
 
-      friend query
+      friend query_base
       operator<= (const query_column& c, ref_bind<T> r)
       {
         return c.less_equal (r);
       }
 
-      friend query
+      friend query_base
       operator<= (ref_bind<T> r, const query_column& c)
       {
         return c.greater_equal (r);
@@ -958,89 +958,89 @@ namespace odb
       // >=
       //
     public:
-      query
+      query_base
       greater_equal (const T& v) const
       {
         return greater_equal (val_bind<T> (v));
       }
 
-      query
+      query_base
       greater_equal (val_bind<T> v) const
       {
         v.prec = prec_;
         v.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += ">=";
         q.append<T, ID> (v, conversion_);
         return q;
       }
 
       template <typename T2>
-      query
+      query_base
       greater_equal (val_bind<T2> v) const
       {
         copy_bind<T, T2> c (v.val);
         return greater_equal (c);
       }
 
-      query
+      query_base
       greater_equal (ref_bind<T> r) const
       {
         r.prec = prec_;
         r.scale = scale_;
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += ">=";
         q.append<T, ID> (r, conversion_);
         return q;
       }
 
-      friend query
+      friend query_base
       operator>= (const query_column& c, const T& v)
       {
         return c.greater_equal (v);
       }
 
-      friend query
+      friend query_base
       operator>= (const T& v, const query_column& c)
       {
         return c.less_equal (v);
       }
 
-      friend query
+      friend query_base
       operator>= (const query_column& c, val_bind<T> v)
       {
         return c.greater_equal (v);
       }
 
-      friend query
+      friend query_base
       operator>= (val_bind<T> v, const query_column& c)
       {
         return c.less_equal (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator>= (const query_column& c, val_bind<T2> v)
       {
         return c.greater_equal (v);
       }
 
       template <typename T2>
-      friend query
+      friend query_base
       operator>= (val_bind<T2> v, const query_column& c)
       {
         return c.less_equal (v);
       }
 
-      friend query
+      friend query_base
       operator>= (const query_column& c, ref_bind<T> r)
       {
         return c.greater_equal (r);
       }
 
-      friend query
+      friend query_base
       operator>= (ref_bind<T> r, const query_column& c)
       {
         return c.less_equal (r);
@@ -1050,84 +1050,84 @@ namespace odb
       //
     public:
       template <typename T2, database_type_id ID2>
-      query
+      query_base
       operator== (const query_column<T2, ID2>& c) const
       {
         // We can compare columns only if we can compare their C++ types.
         //
         (void) (sizeof (type_instance<T> () == type_instance<T2> ()));
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "=";
         q.append (c.table (), c.column ());
         return q;
       }
 
       template <typename T2, database_type_id ID2>
-      query
+      query_base
       operator!= (const query_column<T2, ID2>& c) const
       {
         // We can compare columns only if we can compare their C++ types.
         //
         (void) (sizeof (type_instance<T> () != type_instance<T2> ()));
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "!=";
         q.append (c.table (), c.column ());
         return q;
       }
 
       template <typename T2, database_type_id ID2>
-      query
+      query_base
       operator< (const query_column<T2, ID2>& c) const
       {
         // We can compare columns only if we can compare their C++ types.
         //
         (void) (sizeof (type_instance<T> () < type_instance<T2> ()));
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "<";
         q.append (c.table (), c.column ());
         return q;
       }
 
       template <typename T2, database_type_id ID2>
-      query
+      query_base
       operator> (const query_column<T2, ID2>& c) const
       {
         // We can compare columns only if we can compare their C++ types.
         //
         (void) (sizeof (type_instance<T> () > type_instance<T2> ()));
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += ">";
         q.append (c.table (), c.column ());
         return q;
       }
 
       template <typename T2, database_type_id ID2>
-      query
+      query_base
       operator<= (const query_column<T2, ID2>& c) const
       {
         // We can compare columns only if we can compare their C++ types.
         //
         (void) (sizeof (type_instance<T> () <= type_instance<T2> ()));
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "<=";
         q.append (c.table (), c.column ());
         return q;
       }
 
       template <typename T2, database_type_id ID2>
-      query
+      query_base
       operator>= (const query_column<T2, ID2>& c) const
       {
         // We can compare columns only if we can compare their C++ types.
         //
         (void) (sizeof (type_instance<T> () >= type_instance<T2> ()));
 
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += ">=";
         q.append (c.table (), c.column ());
         return q;
@@ -1174,18 +1174,18 @@ namespace odb
       // is_null, is_not_null
       //
     public:
-      query
+      query_base
       is_null () const
       {
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "IS NULL";
         return q;
       }
 
-      query
+      query_base
       is_not_null () const
       {
-        query q (table_, column_);
+        query_base q (table_, column_);
         q += "IS NOT NULL";
         return q;
       }
@@ -1226,37 +1226,37 @@ namespace odb
     // query fragments (e.g., ORDER BY).
     //
     template <typename T, database_type_id ID>
-    inline query
+    inline query_base
     operator+ (const query_column<T, ID>& c, const std::string& s)
     {
-      query q (c.table (), c.column ());
+      query_base q (c.table (), c.column ());
       q += s;
       return q;
     }
 
     template <typename T, database_type_id ID>
-    inline query
+    inline query_base
     operator+ (const std::string& s, const query_column<T, ID>& c)
     {
-      query q (s);
+      query_base q (s);
       q.append (c.table (), c.column ());
       return q;
     }
 
     template <typename T, database_type_id ID>
-    inline query
-    operator+ (const query_column<T, ID>& c, const query& q)
+    inline query_base
+    operator+ (const query_column<T, ID>& c, const query_base& q)
     {
-      query r (c.table (), c.column ());
+      query_base r (c.table (), c.column ());
       r += q;
       return r;
     }
 
     template <typename T, database_type_id ID>
-    inline query
-    operator+ (const query& q, const query_column<T, ID>& c)
+    inline query_base
+    operator+ (const query_base& q, const query_column<T, ID>& c)
     {
-      query r (q);
+      query_base r (q);
       r.append (c.table (), c.column ());
       return r;
     }
@@ -1538,7 +1538,6 @@ namespace odb
       query_param_impl (val_bind<T> v)
           : query_param (0),
             image_ (0) // Don't cache, don't free.
-
       {
         init (v.val);
       }
@@ -1585,7 +1584,6 @@ namespace odb
       query_param_impl (val_bind<T> v)
           : query_param (0),
             image_ (0) // Don't cache, don't free.
-
       {
         init (v.val);
       }
@@ -1826,13 +1824,75 @@ namespace odb
   }
 }
 
-// odb::query specialization for Oracle.
+// odb::oracle::query and odb::query specialization for Oracle.
 //
 namespace odb
 {
+  namespace oracle
+  {
+    template <typename T>
+    class query: public query_base,
+                 public query_selector<T, id_oracle>::columns_type
+    {
+    public:
+      // We don't define any typedefs here since they may clash with
+      // column names defined by our base type.
+      //
+
+      query ()
+      {
+      }
+
+      explicit
+      query (bool v)
+          : query_base (v)
+      {
+      }
+
+      explicit
+      query (const char* q)
+          : query_base (q)
+      {
+      }
+
+      explicit
+      query (const std::string& q)
+          : query_base (q)
+      {
+      }
+
+      template <typename T2>
+      explicit
+      query (val_bind<T2> v)
+          : query_base (v)
+      {
+      }
+
+      template <typename T2>
+      explicit
+      query (ref_bind<T2> r)
+          : query_base (r)
+      {
+      }
+
+      query (const query_base& q)
+          : query_base (q)
+      {
+      }
+
+      template <database_type_id ID>
+      query (const query_column<bool, ID>& qc)
+          : query_base (qc)
+      {
+      }
+    };
+  }
+
+  // Derive odb::query from odb::oracle::query so that it can be
+  // implicitly converted in oracle::database::query() calls.
+  //
   template <typename T>
-  class query<T, oracle::query>: public oracle::query,
-                                 public query_selector<T>::columns_type
+  class query<T, oracle::query_base>: public oracle::query<T>
   {
   public:
     // We don't define any typedefs here since they may clash with
@@ -1845,44 +1905,44 @@ namespace odb
 
     explicit
     query (bool v)
-        : oracle::query (v)
+        : oracle::query<T> (v)
     {
     }
 
     explicit
     query (const char* q)
-        : oracle::query (q)
+        : oracle::query<T> (q)
     {
     }
 
     explicit
     query (const std::string& q)
-        : oracle::query (q)
+        : oracle::query<T> (q)
     {
     }
 
     template <typename T2>
     explicit
     query (oracle::val_bind<T2> v)
-        : oracle::query (oracle::query (v))
+        : oracle::query<T> (v)
     {
     }
 
     template <typename T2>
     explicit
     query (oracle::ref_bind<T2> r)
-        : oracle::query (oracle::query (r))
+        : oracle::query<T> (r)
     {
     }
 
-    query (const oracle::query& q)
-        : oracle::query (q)
+    query (const oracle::query_base& q)
+        : oracle::query<T> (q)
     {
     }
 
     template <oracle::database_type_id ID>
     query (const oracle::query_column<bool, ID>& qc)
-        : oracle::query (qc)
+        : oracle::query<T> (qc)
     {
     }
   };
diff --git a/odb/oracle/query.ixx b/odb/oracle/query.ixx
index 2a41ae4..75e7bfe 100644
--- a/odb/oracle/query.ixx
+++ b/odb/oracle/query.ixx
@@ -7,7 +7,7 @@ namespace odb
   namespace oracle
   {
     template <typename T, database_type_id ID>
-    inline void query::
+    inline void query_base::
     append (val_bind<T> v, const char* conv)
     {
       add (
@@ -17,7 +17,7 @@ namespace odb
     }
 
     template <typename T, database_type_id ID>
-    inline void query::
+    inline void query_base::
     append (ref_bind<T> r, const char* conv)
     {
       add (
diff --git a/odb/oracle/query.txx b/odb/oracle/query.txx
index 47bf513..5921efe 100644
--- a/odb/oracle/query.txx
+++ b/odb/oracle/query.txx
@@ -6,12 +6,12 @@ namespace odb
 {
   namespace oracle
   {
-    // query
+    // query_base
     //
 
     template <database_type_id ID>
-    query::
-    query (const query_column<bool, ID>& c)
+    query_base::
+    query_base (const query_column<bool, ID>& c)
         : binding_ (0, 0)
     {
       // Cannot use IS TRUE here since database type can be a non-
@@ -26,10 +26,10 @@ namespace odb
     // query_column
     //
     template <typename T, database_type_id ID>
-    query query_column<T, ID>::
+    query_base query_column<T, ID>::
     in (const T& v1, const T& v2) const
     {
-      query q (table_, column_);
+      query_base q (table_, column_);
       q += "IN (";
       q.append<T, ID> (val_bind<T> (v1, prec_, scale_), conversion_);
       q += ",";
@@ -39,10 +39,10 @@ namespace odb
     }
 
     template <typename T, database_type_id ID>
-    query query_column<T, ID>::
+    query_base query_column<T, ID>::
     in (const T& v1, const T& v2, const T& v3) const
     {
-      query q (table_, column_);
+      query_base q (table_, column_);
       q += "IN (";
       q.append<T, ID> (val_bind<T> (v1, prec_, scale_), conversion_);
       q += ",";
@@ -54,10 +54,10 @@ namespace odb
     }
 
     template <typename T, database_type_id ID>
-    query query_column<T, ID>::
+    query_base query_column<T, ID>::
     in (const T& v1, const T& v2, const T& v3, const T& v4) const
     {
-      query q (table_, column_);
+      query_base q (table_, column_);
       q += "IN (";
       q.append<T, ID> (val_bind<T> (v1, prec_, scale_), conversion_);
       q += ",";
@@ -71,10 +71,10 @@ namespace odb
     }
 
     template <typename T, database_type_id ID>
-    query query_column<T, ID>::
+    query_base query_column<T, ID>::
     in (const T& v1, const T& v2, const T& v3, const T& v4, const T& v5) const
     {
-      query q (table_, column_);
+      query_base q (table_, column_);
       q += "IN (";
       q.append<T, ID> (val_bind<T> (v1, prec_, scale_), conversion_);
       q += ",";
@@ -91,10 +91,10 @@ namespace odb
 
     template <typename T, database_type_id ID>
     template <typename I>
-    query query_column<T, ID>::
+    query_base query_column<T, ID>::
     in_range (I begin, I end) const
     {
-      query q (table_, column_);
+      query_base q (table_, column_);
       q += "IN (";
 
       for (I i (begin); i != end; ++i)
@@ -104,6 +104,7 @@ namespace odb
 
         q.append<T, ID> (val_bind<T> (*i, prec_, scale_), conversion_);
       }
+
       q += ")";
       return q;
     }
diff --git a/odb/oracle/simple-object-result.hxx b/odb/oracle/simple-object-result.hxx
index cbfe8c5..cde1a18 100644
--- a/odb/oracle/simple-object-result.hxx
+++ b/odb/oracle/simple-object-result.hxx
@@ -14,7 +14,7 @@
 #include <odb/details/shared-ptr.hxx>
 
 #include <odb/oracle/version.hxx>
-#include <odb/oracle/forward.hxx> // query
+#include <odb/oracle/forward.hxx> // query_base
 #include <odb/oracle/statement.hxx>
 
 namespace odb
@@ -27,11 +27,11 @@ namespace odb
     public:
       typedef odb::object_result_impl<T> base_type;
 
-      typedef typename base_type::object_type object_type;
-      typedef typename base_type::object_traits object_traits;
       typedef typename base_type::id_type id_type;
-
+      typedef typename base_type::object_type object_type;
       typedef typename base_type::pointer_type pointer_type;
+
+      typedef object_traits_impl<object_type, id_oracle> object_traits;
       typedef typename base_type::pointer_traits pointer_traits;
 
       typedef typename object_traits::statements_type statements_type;
@@ -39,7 +39,7 @@ namespace odb
       virtual
       ~object_result_impl ();
 
-      object_result_impl (const query&,
+      object_result_impl (const query_base&,
                           details::shared_ptr<select_statement>,
                           statements_type&);
 
diff --git a/odb/oracle/simple-object-result.txx b/odb/oracle/simple-object-result.txx
index ec0d1f5..b36eb3b 100644
--- a/odb/oracle/simple-object-result.txx
+++ b/odb/oracle/simple-object-result.txx
@@ -33,7 +33,7 @@ namespace odb
 
     template <typename T>
     object_result_impl<T>::
-    object_result_impl (const query&,
+    object_result_impl (const query_base&,
                         details::shared_ptr<select_statement> statement,
                         statements_type& statements)
         : base_type (statements.connection ().database ()),
diff --git a/odb/oracle/simple-object-statements.hxx b/odb/oracle/simple-object-statements.hxx
index e33a7e7..46ed9ca 100644
--- a/odb/oracle/simple-object-statements.hxx
+++ b/odb/oracle/simple-object-statements.hxx
@@ -147,7 +147,7 @@ namespace odb
     struct optimistic_data<T, true>
     {
       typedef T object_type;
-      typedef odb::object_traits<object_type> object_traits;
+      typedef object_traits_impl<object_type, id_oracle> object_traits;
 
       optimistic_data (bind*);
 
@@ -170,7 +170,7 @@ namespace odb
     {
     public:
       typedef T object_type;
-      typedef odb::object_traits<object_type> object_traits;
+      typedef object_traits_impl<object_type, id_oracle> object_traits;
       typedef typename object_traits::id_type id_type;
       typedef typename object_traits::pointer_type pointer_type;
       typedef typename object_traits::image_type image_type;
diff --git a/odb/oracle/statement-cache.hxx b/odb/oracle/statement-cache.hxx
index d4d65ca..4163b36 100644
--- a/odb/oracle/statement-cache.hxx
+++ b/odb/oracle/statement-cache.hxx
@@ -32,7 +32,7 @@ namespace odb
       statement_cache (connection& conn): conn_ (conn) {}
 
       template <typename T>
-      typename object_traits<T>::statements_type&
+      typename object_traits_impl<T, id_oracle>::statements_type&
       find_object ();
 
       template <typename T>
diff --git a/odb/oracle/statement-cache.txx b/odb/oracle/statement-cache.txx
index 6f62b8f..77bed7e 100644
--- a/odb/oracle/statement-cache.txx
+++ b/odb/oracle/statement-cache.txx
@@ -7,10 +7,13 @@ namespace odb
   namespace oracle
   {
     template <typename T>
-    typename object_traits<T>::statements_type& statement_cache::
+    typename object_traits_impl<T, id_oracle>::statements_type&
+    statement_cache::
     find_object ()
     {
-      typedef typename object_traits<T>::statements_type statements_type;
+      typedef
+      typename object_traits_impl<T, id_oracle>::statements_type
+      statements_type;
 
       map::iterator i (map_.find (&typeid (T)));
 
diff --git a/odb/oracle/view-result.hxx b/odb/oracle/view-result.hxx
index f44911a..ccbf57b 100644
--- a/odb/oracle/view-result.hxx
+++ b/odb/oracle/view-result.hxx
@@ -14,7 +14,7 @@
 #include <odb/details/shared-ptr.hxx>
 
 #include <odb/oracle/version.hxx>
-#include <odb/oracle/forward.hxx> // query, view_statements
+#include <odb/oracle/forward.hxx> // query_base, view_statements
 #include <odb/oracle/statement.hxx>
 
 namespace odb
@@ -28,9 +28,9 @@ namespace odb
       typedef odb::view_result_impl<T> base_type;
 
       typedef typename base_type::view_type view_type;
-      typedef typename base_type::view_traits view_traits;
-
       typedef typename base_type::pointer_type pointer_type;
+
+      typedef view_traits_impl<view_type, id_oracle> view_traits;
       typedef typename base_type::pointer_traits pointer_traits;
 
       typedef view_statements<view_type> statements_type;
@@ -38,7 +38,7 @@ namespace odb
       virtual
       ~view_result_impl ();
 
-      view_result_impl (const query&,
+      view_result_impl (const query_base&,
                         details::shared_ptr<select_statement>,
                         statements_type&);
 
diff --git a/odb/oracle/view-result.txx b/odb/oracle/view-result.txx
index dc5cd6a..248ef76 100644
--- a/odb/oracle/view-result.txx
+++ b/odb/oracle/view-result.txx
@@ -31,7 +31,7 @@ namespace odb
 
     template <typename T>
     view_result_impl<T>::
-    view_result_impl (const query&,
+    view_result_impl (const query_base&,
                       details::shared_ptr<select_statement> statement,
                       statements_type& statements)
         : base_type (statements.connection ().database ()),
diff --git a/odb/oracle/view-statements.hxx b/odb/oracle/view-statements.hxx
index 4794e4f..aadf094 100644
--- a/odb/oracle/view-statements.hxx
+++ b/odb/oracle/view-statements.hxx
@@ -26,7 +26,7 @@ namespace odb
     {
     public:
       typedef T view_type;
-      typedef odb::view_traits<view_type> view_traits;
+      typedef view_traits_impl<view_type, id_oracle> view_traits;
       typedef typename view_traits::pointer_type pointer_type;
       typedef typename view_traits::image_type image_type;