> What I'm planning is a client-server database (yes, I think big) and I
> was wondering whether Metacard might be better suited for my purposes.
> (Frankly, I doubt I can get Hypercard to do it without a database
> application behind it.)
Sure you can do it in HC, Steven; you're not thinking big enough. :{`)
But your questions were still pertinent to me, as I am considering
migrating my single user HC db to MetaCard and converting it to multiuser.
> Can multiple copies of Metacard access simultaneously a single stack
> with read and write access? I'll handle record locking myself.
I see this as a "traditional" db approach, not client-server. I think the
issues involved in maintaining data integrity and avoiding corruption from
simultaneous writes make this approach problematical in HC or MC.
> If not, can I use a single Metacard stack to hold the database, with
> other stacks running as seperate sessions querying it?
I know this will work in HC using send and/or request, and presume it will
work in MC (although I don't see "request" in the MC Users Guide index).
Each user has a client stack that can capture/display information; but
there is only one db server stack where the information is filed. There
should be no danger of simultaneous writes if the server queues client
requests and completes each request before processing the next. If
multiple clients can change the same info in the db, you will have to
implement some sort of record locking mechanism.
> Otherwise, if anyone can suggest a way I could use Metacard to develop a
> client-server application, I'd be greatful.
If you want a stand-alone, cross-platform server, the server stack cannot
contain the data because Windows & Unix won't allow an app to modify
itself. In that case the db server app becomes a "middleman" between
stacks requesting data storage/retrieval and stacks designed as data
repositories.
Hope this helps!
Rob Cozens, CCW
http://www.serendipitysoftware.com/who.html
"And I, which was two fooles, do so grow three;
Who are a little wise, the best fooles bee."
from "The Triple Foole" by John Donne (1572-1631)
