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, 2 insertions, 2 deletions

diff --git a/odb/pgsql/transaction-impl.cxx b/odb/pgsql/transaction-impl.cxx
index eb93361..81aaf08 100644
--- a/odb/pgsql/transaction-impl.cxx
+++ b/odb/pgsql/transaction-impl.cxx
@@ -19,8 +19,8 @@ namespace odb
   namespace pgsql
   {
     transaction_impl::
-    transaction_impl (database_type& db)
-        : odb::transaction_impl (db), connection_ (db.connection ())
+    transaction_impl (connection_ptr c)
+        : odb::transaction_impl (c->database (), *c), connection_ (c)
     {
       result_ptr r (PQexec (connection_->handle (), "begin"));
       PGresult* h (r.get ());