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, 16 insertions, 9 deletions

diff --git a/odb/tracer/database.cxx b/odb/tracer/database.cxx
index 1359a26..90cfdfd 100644
--- a/odb/tracer/database.cxx
+++ b/odb/tracer/database.cxx
@@ -3,8 +3,8 @@
 // copyright : Copyright (c) 2009-2011 Code Synthesis Tools CC
 // license   : GNU GPL v2; see accompanying LICENSE file
 
-#include <odb/transaction.hxx>
 #include <odb/tracer/database.hxx>
+#include <odb/tracer/connection.hxx>
 
 namespace odb
 {
@@ -15,19 +15,26 @@ namespace odb
     {
     }
 
-    unsigned long long database::
-    execute (const char*, std::size_t)
+    transaction_impl* database::
+    begin ()
     {
-      return 0;
+      return connection ()->begin ();
     }
 
-    transaction_impl* database::
-    begin ()
+    inline connection_ptr database::
+    connection ()
     {
-      if (odb::transaction::has_current ())
-        throw already_in_transaction ();
+      // Go through the virtual connection_() function instead of
+      // directly to allow overriding.
+      //
+      return connection_ptr (
+        static_cast<tracer::connection*> (connection_ ()));
+    }
 
-      return new transaction_impl (*this);
+    odb::connection* database::
+    connection_ ()
+    {
+      return new (details::shared) connection_type (*this);
     }
   }
 }