Add support for mapping char[N] to CHAR/VARCHAR database types

Also improve query support for arrays (decaying).

1 files changed, 279 insertions, 118 deletions

diff --git a/odb/mysql/query.hxx b/odb/mysql/query.hxx
index b86818e..5af564b 100644
--- a/odb/mysql/query.hxx
+++ b/odb/mysql/query.hxx
@@ -32,23 +32,72 @@ namespace odb
   namespace mysql
   {
     template <typename T>
-    class val_bind
+    struct val_bind
     {
-    public:
+      typedef const T& type;
+
+      explicit
+      val_bind (type v): val (v) {}
+
+      type val;
+    };
+
+    template <typename T, std::size_t N>
+    struct val_bind<T[N]>
+    {
+      typedef const T* type;
+
       explicit
-      val_bind (const T& v): val (v) {}
+      val_bind (type v): val (v) {}
 
-      const T& val;
+      type val;
     };
 
     template <typename T>
-    class ref_bind
+    struct ref_bind
+    {
+      typedef const T& type;
+
+      explicit
+      ref_bind (type r): ref (r) {}
+
+      const void*
+      ptr () const {return &ref;}
+
+      type ref;
+    };
+
+    template <typename T, std::size_t N>
+    struct ref_bind<T[N]>
+    {
+      typedef const T* type;
+
+      explicit
+      ref_bind (type r): ref (r) {}
+
+      // Allow implicit conversion from decayed ref_bind's.
+      //
+      ref_bind (ref_bind<T*> r): ref (r.ref) {}
+      ref_bind (ref_bind<const T*> r): ref (r.ref) {}
+
+      const void*
+      ptr () const {return ref;}
+
+      type ref;
+    };
+
+    template <typename T, database_type_id ID>
+    struct val_bind_typed: val_bind<T>
     {
-    public:
       explicit
-      ref_bind (const T& r): ref (r) {}
+      val_bind_typed (typename val_bind<T>::type v): val_bind<T> (v) {}
+    };
 
-      const T& ref;
+    template <typename T, database_type_id ID>
+    struct ref_bind_typed: ref_bind<T>
+    {
+      explicit
+      ref_bind_typed (typename ref_bind<T>::type r): ref_bind<T> (r) {}
     };
 
     struct LIBODB_MYSQL_EXPORT query_param: details::shared_base
@@ -69,10 +118,7 @@ namespace odb
       bind (MYSQL_BIND*) = 0;
 
     protected:
-      query_param (const void* value)
-          : value_ (value)
-      {
-      }
+      query_param (const void* value) : value_ (value) {}
 
     protected:
       const void* value_;
@@ -144,8 +190,15 @@ namespace odb
       query_base (val_bind<T> v)
         : binding_ (0, 0)
       {
-        append<T, type_traits<T>::db_type_id> (
-          v, details::conversion<T>::to ());
+        *this += v;
+      }
+
+      template <typename T, database_type_id ID>
+      explicit
+      query_base (val_bind_typed<T, ID> v)
+        : binding_ (0, 0)
+      {
+        *this += v;
       }
 
       template <typename T>
@@ -153,8 +206,15 @@ namespace odb
       query_base (ref_bind<T> r)
         : binding_ (0, 0)
       {
-        append<T, type_traits<T>::db_type_id> (
-          r, details::conversion<T>::to ());
+        *this += r;
+      }
+
+      template <typename T, database_type_id ID>
+      explicit
+      query_base (ref_bind_typed<T, ID> r)
+        : binding_ (0, 0)
+      {
+        *this += r;
       }
 
       template <database_type_id ID>
@@ -215,6 +275,13 @@ namespace odb
         return val_bind<T> (x);
       }
 
+      template <database_type_id ID, typename T>
+      static val_bind_typed<T, ID>
+      _val (const T& x)
+      {
+        return val_bind_typed<T, ID> (x);
+      }
+
       template <typename T>
       static ref_bind<T>
       _ref (const T& x)
@@ -222,6 +289,13 @@ namespace odb
         return ref_bind<T> (x);
       }
 
+      template <database_type_id ID, typename T>
+      static ref_bind_typed<T, ID>
+      _ref (const T& x)
+      {
+        return ref_bind_typed<T, ID> (x);
+      }
+
     public:
       query_base&
       operator+= (const query_base&);
@@ -242,6 +316,17 @@ namespace odb
         return *this;
       }
 
+      template <typename T, database_type_id ID>
+      query_base&
+      operator+= (val_bind_typed<T, ID> v)
+      {
+        // We are not using default type_traits so no default conversion
+        // either.
+        //
+        append<T, ID> (v, 0);
+        return *this;
+      }
+
       template <typename T>
       query_base&
       operator+= (ref_bind<T> r)
@@ -251,6 +336,17 @@ namespace odb
         return *this;
       }
 
+      template <typename T, database_type_id ID>
+      query_base&
+      operator+= (ref_bind_typed<T, ID> r)
+      {
+        // We are not using default type_traits so no default conversion
+        // either.
+        //
+        append<T, ID> (r, 0);
+        return *this;
+      }
+
       // Implementation details.
       //
     public:
@@ -312,16 +408,26 @@ namespace odb
 
     template <typename T>
     inline query_base
-    operator+ (const query_base& q, ref_bind<T> b)
+    operator+ (val_bind<T> b, const query_base& q)
+    {
+      query_base r;
+      r += b;
+      r += q;
+      return r;
+    }
+
+    template <typename T, database_type_id ID>
+    inline query_base
+    operator+ (const query_base& q, val_bind_typed<T, ID> b)
     {
       query_base r (q);
       r += b;
       return r;
     }
 
-    template <typename T>
+    template <typename T, database_type_id ID>
     inline query_base
-    operator+ (val_bind<T> b, const query_base& q)
+    operator+ (val_bind_typed<T, ID> b, const query_base& q)
     {
       query_base r;
       r += b;
@@ -331,6 +437,15 @@ namespace odb
 
     template <typename T>
     inline query_base
+    operator+ (const query_base& q, ref_bind<T> b)
+    {
+      query_base r (q);
+      r += b;
+      return r;
+    }
+
+    template <typename T>
+    inline query_base
     operator+ (ref_bind<T> b, const query_base& q)
     {
       query_base r;
@@ -339,6 +454,25 @@ namespace odb
       return r;
     }
 
+    template <typename T, database_type_id ID>
+    inline query_base
+    operator+ (const query_base& q, ref_bind_typed<T, ID> b)
+    {
+      query_base r (q);
+      r += b;
+      return r;
+    }
+
+    template <typename T, database_type_id ID>
+    inline query_base
+    operator+ (ref_bind_typed<T, ID> b, const query_base& q)
+    {
+      query_base r;
+      r += b;
+      r += q;
+      return r;
+    }
+
     inline query_base
     operator+ (const query_base& q, const std::string& s)
     {
@@ -366,16 +500,26 @@ namespace odb
 
     template <typename T>
     inline query_base
-    operator+ (const std::string& s, ref_bind<T> b)
+    operator+ (val_bind<T> b, const std::string& s)
+    {
+      query_base r;
+      r += b;
+      r += s;
+      return r;
+    }
+
+    template <typename T, database_type_id ID>
+    inline query_base
+    operator+ (const std::string& s, val_bind_typed<T, ID> b)
     {
       query_base r (s);
       r += b;
       return r;
     }
 
-    template <typename T>
+    template <typename T, database_type_id ID>
     inline query_base
-    operator+ (val_bind<T> b, const std::string& s)
+    operator+ (val_bind_typed<T, ID> b, const std::string& s)
     {
       query_base r;
       r += b;
@@ -385,6 +529,15 @@ namespace odb
 
     template <typename T>
     inline query_base
+    operator+ (const std::string& s, ref_bind<T> b)
+    {
+      query_base r (s);
+      r += b;
+      return r;
+    }
+
+    template <typename T>
+    inline query_base
     operator+ (ref_bind<T> b, const std::string& s)
     {
       query_base r;
@@ -393,6 +546,25 @@ namespace odb
       return r;
     }
 
+    template <typename T, database_type_id ID>
+    inline query_base
+    operator+ (const std::string& s, ref_bind_typed<T, ID> b)
+    {
+      query_base r (s);
+      r += b;
+      return r;
+    }
+
+    template <typename T, database_type_id ID>
+    inline query_base
+    operator+ (ref_bind_typed<T, ID> b, const std::string& s)
+    {
+      query_base r;
+      r += b;
+      r += s;
+      return r;
+    }
+
     LIBODB_MYSQL_EXPORT query_base
     operator&& (const query_base& x, const query_base& y);
 
@@ -442,23 +614,11 @@ namespace odb
       const char* conversion_;
     };
 
-    template <typename T, typename T2>
-    class copy_bind: public val_bind<T>
-    {
-    public:
-      explicit
-      copy_bind (const T2& v): val_bind<T> (val), val (v) {}
-
-      const T val;
-    };
-
-    template <typename T>
-    const T&
-    type_instance ();
-
     template <typename T, database_type_id ID>
     struct query_column: query_column_base
     {
+      typedef typename decay_traits<T>::type decayed_type;
+
       // Note that we keep shallow copies of the table, column, and conversion
       // expression. The latter can be NULL.
       //
@@ -493,16 +653,17 @@ namespace odb
       //
     public:
       query_base
-      in (const T&, const T&) const;
+      in (decayed_type, decayed_type) const;
 
       query_base
-      in (const T&, const T&, const T&) const;
+      in (decayed_type, decayed_type, decayed_type) const;
 
       query_base
-      in (const T&, const T&, const T&, const T&) const;
+      in (decayed_type, decayed_type, decayed_type, decayed_type) const;
 
       query_base
-      in (const T&, const T&, const T&, const T&, const T&) const;
+      in (decayed_type, decayed_type, decayed_type, decayed_type,
+          decayed_type) const;
 
       template <typename I>
       query_base
@@ -512,7 +673,7 @@ namespace odb
       //
     public:
       query_base
-      equal (const T& v) const
+      equal (decayed_type v) const
       {
         return equal (val_bind<T> (v));
       }
@@ -530,8 +691,7 @@ namespace odb
       query_base
       equal (val_bind<T2> v) const
       {
-        copy_bind<T, T2> c (v.val);
-        return equal (c);
+        return equal (val_bind<T> (decayed_type (v.val)));
       }
 
       query_base
@@ -544,13 +704,13 @@ namespace odb
       }
 
       friend query_base
-      operator== (const query_column& c, const T& v)
+      operator== (const query_column& c, decayed_type v)
       {
         return c.equal (v);
       }
 
       friend query_base
-      operator== (const T& v, const query_column& c)
+      operator== (decayed_type v, const query_column& c)
       {
         return c.equal (v);
       }
@@ -597,7 +757,7 @@ namespace odb
       //
     public:
       query_base
-      unequal (const T& v) const
+      unequal (decayed_type v) const
       {
         return unequal (val_bind<T> (v));
       }
@@ -615,8 +775,7 @@ namespace odb
       query_base
       unequal (val_bind<T2> v) const
       {
-        copy_bind<T, T2> c (v.val);
-        return unequal (c);
+        return unequal (val_bind<T> (decayed_type (v.val)));
       }
 
       query_base
@@ -629,13 +788,13 @@ namespace odb
       }
 
       friend query_base
-      operator!= (const query_column& c, const T& v)
+      operator!= (const query_column& c, decayed_type v)
       {
         return c.unequal (v);
       }
 
       friend query_base
-      operator!= (const T& v, const query_column& c)
+      operator!= (decayed_type v, const query_column& c)
       {
         return c.unequal (v);
       }
@@ -682,7 +841,7 @@ namespace odb
       //
     public:
       query_base
-      less (const T& v) const
+      less (decayed_type v) const
       {
         return less (val_bind<T> (v));
       }
@@ -700,8 +859,7 @@ namespace odb
       query_base
       less (val_bind<T2> v) const
       {
-        copy_bind<T, T2> c (v.val);
-        return less (c);
+        return less (val_bind<T> (decayed_type (v.val)));
       }
 
       query_base
@@ -714,13 +872,13 @@ namespace odb
       }
 
       friend query_base
-      operator< (const query_column& c, const T& v)
+      operator< (const query_column& c, decayed_type v)
       {
         return c.less (v);
       }
 
       friend query_base
-      operator< (const T& v, const query_column& c)
+      operator< (decayed_type v, const query_column& c)
       {
         return c.greater (v);
       }
@@ -767,7 +925,7 @@ namespace odb
       //
     public:
       query_base
-      greater (const T& v) const
+      greater (decayed_type v) const
       {
         return greater (val_bind<T> (v));
       }
@@ -785,8 +943,7 @@ namespace odb
       query_base
       greater (val_bind<T2> v) const
       {
-        copy_bind<T, T2> c (v.val);
-        return greater (c);
+        return greater (val_bind<T> (decayed_type (v.val)));
       }
 
       query_base
@@ -799,13 +956,13 @@ namespace odb
       }
 
       friend query_base
-      operator> (const query_column& c, const T& v)
+      operator> (const query_column& c, decayed_type v)
       {
         return c.greater (v);
       }
 
       friend query_base
-      operator> (const T& v, const query_column& c)
+      operator> (decayed_type v, const query_column& c)
       {
         return c.less (v);
       }
@@ -852,7 +1009,7 @@ namespace odb
       //
     public:
       query_base
-      less_equal (const T& v) const
+      less_equal (decayed_type v) const
       {
         return less_equal (val_bind<T> (v));
       }
@@ -870,8 +1027,7 @@ namespace odb
       query_base
       less_equal (val_bind<T2> v) const
       {
-        copy_bind<T, T2> c (v.val);
-        return less_equal (c);
+        return less_equal (val_bind<T> (decayed_type (v.val)));
       }
 
       query_base
@@ -884,13 +1040,13 @@ namespace odb
       }
 
       friend query_base
-      operator<= (const query_column& c, const T& v)
+      operator<= (const query_column& c, decayed_type v)
       {
         return c.less_equal (v);
       }
 
       friend query_base
-      operator<= (const T& v, const query_column& c)
+      operator<= (decayed_type v, const query_column& c)
       {
         return c.greater_equal (v);
       }
@@ -937,7 +1093,7 @@ namespace odb
       //
     public:
       query_base
-      greater_equal (const T& v) const
+      greater_equal (decayed_type v) const
       {
         return greater_equal (val_bind<T> (v));
       }
@@ -955,8 +1111,7 @@ namespace odb
       query_base
       greater_equal (val_bind<T2> v) const
       {
-        copy_bind<T, T2> c (v.val);
-        return greater_equal (c);
+        return greater_equal (val_bind<T> (decayed_type (v.val)));
       }
 
       query_base
@@ -969,13 +1124,13 @@ namespace odb
       }
 
       friend query_base
-      operator>= (const query_column& c, const T& v)
+      operator>= (const query_column& c, decayed_type v)
       {
         return c.greater_equal (v);
       }
 
       friend query_base
-      operator>= (const T& v, const query_column& c)
+      operator>= (decayed_type v, const query_column& c)
       {
         return c.less_equal (v);
       }
@@ -1027,7 +1182,8 @@ namespace odb
       {
         // We can compare columns only if we can compare their C++ types.
         //
-        (void) (sizeof (type_instance<T> () == type_instance<T2> ()));
+        (void) (sizeof (decay_traits<T>::instance () ==
+                        decay_traits<T2>::instance ()));
 
         query_base q (table_, column_);
         q += "=";
@@ -1041,7 +1197,8 @@ namespace odb
       {
         // We can compare columns only if we can compare their C++ types.
         //
-        (void) (sizeof (type_instance<T> () != type_instance<T2> ()));
+        (void) (sizeof (decay_traits<T>::instance () !=
+                        decay_traits<T2>::instance ()));
 
         query_base q (table_, column_);
         q += "!=";
@@ -1055,7 +1212,8 @@ namespace odb
       {
         // We can compare columns only if we can compare their C++ types.
         //
-        (void) (sizeof (type_instance<T> () < type_instance<T2> ()));
+        (void) (sizeof (decay_traits<T>::instance () <
+                        decay_traits<T2>::instance ()));
 
         query_base q (table_, column_);
         q += "<";
@@ -1069,7 +1227,8 @@ namespace odb
       {
         // We can compare columns only if we can compare their C++ types.
         //
-        (void) (sizeof (type_instance<T> () > type_instance<T2> ()));
+        (void) (sizeof (decay_traits<T>::instance () >
+                        decay_traits<T2>::instance ()));
 
         query_base q (table_, column_);
         q += ">";
@@ -1083,7 +1242,8 @@ namespace odb
       {
         // We can compare columns only if we can compare their C++ types.
         //
-        (void) (sizeof (type_instance<T> () <= type_instance<T2> ()));
+        (void) (sizeof (decay_traits<T>::instance () <=
+                        decay_traits<T2>::instance ()));
 
         query_base q (table_, column_);
         q += "<=";
@@ -1097,7 +1257,8 @@ namespace odb
       {
         // We can compare columns only if we can compare their C++ types.
         //
-        (void) (sizeof (type_instance<T> () >= type_instance<T2> ()));
+        (void) (sizeof (decay_traits<T>::instance () >=
+                        decay_traits<T2>::instance ()));
 
         query_base q (table_, column_);
         q += ">=";
@@ -1155,7 +1316,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_tiny>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1175,7 +1336,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_tiny>::set_image (image_, is_null, v);
@@ -1188,7 +1349,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_utiny>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1208,7 +1369,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_utiny>::set_image (image_, is_null, v);
@@ -1223,7 +1384,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_short>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1243,7 +1404,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_short>::set_image (image_, is_null, v);
@@ -1256,7 +1417,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_ushort>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1276,7 +1437,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_ushort>::set_image (image_, is_null, v);
@@ -1291,7 +1452,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_long>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1311,7 +1472,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_long>::set_image (image_, is_null, v);
@@ -1324,7 +1485,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_ulong>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1344,7 +1505,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_ulong>::set_image (image_, is_null, v);
@@ -1359,7 +1520,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_longlong>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1379,7 +1540,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_longlong>::set_image (image_, is_null, v);
@@ -1392,7 +1553,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_ulonglong>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1412,7 +1573,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_ulonglong>::set_image (image_, is_null, v);
@@ -1427,7 +1588,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_float>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1447,7 +1608,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_float>::set_image (image_, is_null, v);
@@ -1462,7 +1623,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_double>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1482,7 +1643,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_double>::set_image (image_, is_null, v);
@@ -1497,7 +1658,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_decimal>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1517,7 +1678,7 @@ namespace odb
 
     private:
       bool
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         std::size_t size (0), cap (buffer_.capacity ());
@@ -1536,7 +1697,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_date>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1555,7 +1716,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_date>::set_image (image_, is_null, v);
@@ -1570,7 +1731,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_time>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1589,7 +1750,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_time>::set_image (image_, is_null, v);
@@ -1604,7 +1765,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_datetime>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1623,7 +1784,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_datetime>::set_image (image_, is_null, v);
@@ -1638,7 +1799,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_timestamp>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1657,7 +1818,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_timestamp>::set_image (image_, is_null, v);
@@ -1672,7 +1833,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_year>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1692,7 +1853,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         value_traits<T, id_year>::set_image (image_, is_null, v);
@@ -1707,7 +1868,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_string>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1727,7 +1888,7 @@ namespace odb
 
     private:
       bool
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         std::size_t size (0), cap (buffer_.capacity ());
@@ -1746,7 +1907,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_blob>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1766,7 +1927,7 @@ namespace odb
 
     private:
       bool
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         std::size_t size (0), cap (buffer_.capacity ());
@@ -1785,7 +1946,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_bit>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1806,7 +1967,7 @@ namespace odb
 
     private:
       void
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         std::size_t size (0);
@@ -1829,7 +1990,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_enum>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1846,7 +2007,7 @@ namespace odb
 
     private:
       bool
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         return enum_traits::set_image (image_, size_, is_null, v);
@@ -1862,7 +2023,7 @@ namespace odb
     template <typename T>
     struct query_param_impl<T, id_set>: query_param
     {
-      query_param_impl (ref_bind<T> r) : query_param (&r.ref) {}
+      query_param_impl (ref_bind<T> r) : query_param (r.ptr ()) {}
       query_param_impl (val_bind<T> v) : query_param (0) {init (v.val);}
 
       virtual bool
@@ -1882,7 +2043,7 @@ namespace odb
 
     private:
       bool
-      init (const T& v)
+      init (typename decay_traits<T>::type v)
       {
         bool is_null (false); // Can't be NULL.
         std::size_t size (0), cap (buffer_.capacity ());