[gnome-db] connection stacks

[Rodrigo Moya <rodrigo gnome-db org>]

Hi

I've had some discussions with people wanting to use libgda for their
developments, and, after some conversations, I've decided to add support
for connection stacks to libgda.

I don't know if that is the correct term for it, but what it is is a
stack of connections that you use as if they were just one connection.
This is very useful for doing distributed apps, where there can be
multiple databases that need to be accessed.

So, I've started by adding support for distributed transactions:

/*
 * Connection stack functions
 */

gboolean       gda_client_begin_transaction (GdaClient *client,
GdaTransaction *xaction);
gboolean       gda_client_commit_transaction (GdaClient *client,
GdaTransaction *xaction);
gboolean       gda_client_rollback_transaction (GdaClient *client,
GdaTransaction *xaction);

These just iterate over the list of opened connections in the Gdaclient,
and begin/commit/rollback a transaction on each of them.

I will be adding more utility things to this, but I wanted to let people
know what I was doing. I hope you like it.

cheers