G'Day,
Sorry if this seems like it is back again, but I just want to pose some more
questions after taking all the suggestions etc. I received on board and
having done some actual playing instead of just having theoretical reading
knowledge.
Assumptions:
* Using MIDAS
* 3 Tier Model (Presentation, Application, Back End)
* One "Master" Database on Back End Tier
* Bunch of local database copies (One copy per client)
* Clients on presentation layer can either be updaters (can update the
"Master") or subscribers (They want their local copy of the data updated
when there is a change to the "Master") (Potentially Updates could also be
subscribers)
I know we have gone over this, but I still have some questions:
I need to achieve 3 things here:
1. Have multiple updaters all update a "Master" database
I can see how MIDAS could do this. No problem here. This could also be done
with Midware, but then I would have to roll my own equivalent of
TDataSetProvider (In particular) and could get away with the MWTable
TDataSet descendent that comes with MidWare but TClientDataSet would be
better.
2. Have any changes made to the "Master" database via the application server
come back to all the clients in some form so that their local databases can
be updated
Could this be done in some way with MIDAS?? Perhaps have application servers
on the clients that were called from the "Master" application server to
apply updates to the local database copies. The other option would be to do
this with some connection protocol that passes the relevant SQL statements
as strings from the Application Layer to the Clients. This would be easy to
achieve with MidWare
3. Have all subscribers (read only) use their LOCAL data for queries
This is obviously done using local BDE.
>From the 3 issues above I see that:
1. Is made easy and robust with MIDAS OR Tricker & possibly less robust with
MidWare.
2. Is still tricky. Would have to be done without MIDAS.
3. Is simple BDE
Suggestions, corrections etc.??
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--Donovan
Donovan J. Edye [www.edye.wattle.id.au]
Namadgi Systems, Delphi Developer
Web: www.namsys.com.au E-Mail: [EMAIL PROTECTED]
Voice: +61 2 6285-3460 Fax: +61 2 6285-3459
TVisualBasic = Class(None);
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