We are embarking on a grand/huge project which will take us around 1 full year of coding (by 4 developers) to get off the launch pad.

It is a complete Business Management System.

We can use any commercially available RDBMS like Oracle, MS SQL Server, etc. but we are looking out to use freeware and open source RDBMS system like FireBirdSQL, PostgreSQL, etc.

I would like to know as to which is the best RDBMS to use and which has got best support for stable OLEDB Providers. We have experimented with OLEDB Providers which are freeware for FireBird and pgSQL but are not satisfied with their performance and features.

Any suggestions please....

If there are any other Freeware and/or Open Source RDBMS other than listed above with high performing OLEDB Providers please enlighten me.

Yogi Yang

Note: We will be using VB 6 only and none other development tools or compilers! The target software will have to run on Windows9x based PCs (about 60 users) and the RDBMS server will run on Linux/Windows which ever is suitable.

+1  A: 

I'd be as conservative as possible, since your client hardware and software will need tender loving care. Since SQL Server and VB6 (and Windows) all come from Microsoft, I don't see how you have any other choice.

You might even consider using an older version of SQL Server, since the standard OLEDB server and client parts might line up better, and be lighter-weight. Otherwise SQL Server Express on Windows XP I think can serve that many connections. It certainly would have the horsepower.

le dorfier
You mean to say that Oracle XE or MS SQL Server Express 2005 will be able to handle 60 connections at a time without dropping any active connections?I have heard that if the user load increased in both case some connections are dropped and the limitation of size of the database file is bad for us.
I remember SQL Server 7 running on a 90 MHz NT box supporting 60 users and more. Processor speed/RAM capacity/network speed/you name it have all grown by at least a factor of 20 since then. And DBMS software is one category where execution speed **can't** decline over time for marketing reasons.
le dorfier
+1  A: 

The OLE DB providers for SQL Server and SQL Native Client work well with SQL Server Express, as you'd expect from Microsoft, and therefore are an excellent choice for VB6.

As posted previously. DB file size limitation is what we have to take into consideration as both Oracle and MS SQL Server do not support file size larger than 4 GB.
Four GB disks didn't barely exist when Windows 9x (and NT) were the current versions.
le dorfier
SQL Server Express supports a file size of 524,272 terabytes, according to MSDN.
le dorfier
Thanks for enlightning me on this. From what I have read in various reviews of MS SQL Server and Oracle Express Editions I had the impression that they supported upto only 4 GB file size per Database.

We can use any commercially available RDBMS like Oracle, MS SQL Server, etc. but we are looking out to use freeware and open source RDBMS system like FireBirdSQL, PostgreSQL, etc.

What's wrong with the free versions of SQL Server, Oracle, or DB2? They are all significantly more powerful than the alternatives you mentioned and they give you an upgrade path if you need it.

Jonathan Allen
DB File size limitation is the problem. In the software we are going to store complete text documentations in the DB itself.Hope you get my point.
How much disk have you calculated you will need? SQL Server Express max database size according to MSDN: 524,272 terabytes.The only limits I could find are that it will only use 1 processor and 1 GB RAM; both of which are plenty. Or get a licensed version.
le dorfier
+1  A: 

Thanks everyone for your inputs. I was having wrong impression for Oracle as well as MS SQL Server.

From various reviews that I had read in a few IT Mags. Very clearly stated that the Express Editions of Oracle and MS SQL Server have the following limitations: 1. Use only 1 GM RAM 2. Do not support very many connections so if the load on servers increases they will drop a few connections 3. Max file size per Database is limited to 4 GB. 4. They will not take advantage of multiple CPUs present in a PC. 5. They are slower then their Full commercial offerings.

I will have to re-evaluate both Oracle and MS SQL Server.

Again Thanks to all.


I've had good experience with a MSSQL2005 database backend, with VB6 clients upward of 60-100 concurrent client instances... And this was a data-heavy application with A LOT of chatty database traffic, row locking, and what not.

Worked great. Interacting with the database was the least of the problems.

On that note...

Please use parameterized queries, unless you hate yourself and want to suffer needlessly.

Troy Howard