Add odb::connection class

This abstract class represents a connection to the database. One can
use it to start a transaction or to execute a native statement out
of a transaction.

Before we had concrete connection classes in the database runtime
libraries (e.g., odb::mysql::connection). Now these classes derive
from odb::connection.

1 files changed, 12 insertions, 0 deletions

diff --git a/odb/database.ixx b/odb/database.ixx
index bd3fb44..a308bfe 100644
--- a/odb/database.ixx
+++ b/odb/database.ixx
@@ -12,6 +12,18 @@ namespace odb
   {
   }
 
+  inline transaction_impl* database::
+  begin ()
+  {
+    return connection ()->begin ();
+  }
+
+  inline connection_ptr database::
+  connection ()
+  {
+    return connection_ptr (connection_ ());
+  }
+
   template <typename T>
   inline typename object_traits<T>::id_type database::
   persist (T* p)