Re: Oracle & Delphi

Laurent Boutet wrote:

> If I remember, I can configure my Oracle database to allow a max user
> connections (default 15). And then, what is going on after 15 connections
> ???
> What is the aim of this configuration ??? Each connection starts a new
> process on the server ???

The others answer this one pretty well I think.

Only think I can add here is that IMO you need now to decide on what Oracle configuration will service your needs and platform the best. MTS. Allowing dedicated connections. Resource configuration. Etc.

> Is it possible to share connections with DELPHI through my 8 programs on a
> single client computer ????

Yes and no.

Yes. If you have Oracle running in MTS mode, a single process on Oracle can service any number of _different_ client connections (in serial of course).

No. On the Delphi side, the different EXE programs can not share the same TSession and TDatabase objects.

> If I connect twice to the same database from one client, is it considered
> as 1 ou 2 connections ????

That depends on how you've coded the Delphi applications. Let's say you use a TDataModule to encapsulate your TDatabase and TSession objects. These are global and persistant objects for the duration of the program. All your TQuery and TTable objects use the same TDatabase - you are only using one connection.

If you instead have an MDI application. You code that each MDI form creates its own and unique TDatabase and TSession... for each MDI that you open, a new Oracle connection will be made.

This is not really bad - the MDI thing cal work very well if you add threading to the execution of SQL. This means that while the user is waiting for a query to complete in one MDI, he can continue working with a query and results in another MDI.

Again - the decision on what method to use (multiple vs. single connection in Delphi) depends on the requirements of your application.

> what is a good max users connection configuration from your point of
> view???

What is the length of a piece of rope?

I think you are putting the cart in front of the horses. These technical issues are not applicable until you know what you are aiming for. What requirements you need to fulfil.

If a two users use the Delphi app against Oracle on a NT/XP box - then it matters little if a Delphi app opens 1 or 3 connections. Oracle can quite happily run in dedicated connection mode. It matters little if your application is not Oracle tuned.

If you have a 1,000 users out there, connecting to a large Unix SMP box running Oracle - then it matters a lot what your program does ito connections. It is likely to be critical that Oracle runs in MTS mode. And you better make very sure that your Delphi app fully supports and exploits the features and functionality of both Delphi and Oracle.

--
Billy