[fpc-pascal] n-tier development with Free Pascal

Michael Van Canneyt michael at freepascal.org
Sat Jan 24 12:47:40 CET 2009

On Sat, 24 Jan 2009, Graeme Geldenhuys wrote:

> I haven't dabbled into the DB components in FPC and Lazarus much. Does
> Free Pascal have a TClientDataset?  Has anybody done any 3-tier
> development with Free Pascal?

There is not. TBufDataset has 95% of all TClientDataset features, 
but lacks still the easy transport layer and delta application.
(Joost, correct me if I'm wrong).
> The last time I did 3-tier development with Delphi 7 was some 5 years
> ago. I found this link which is a drop in replacement for the Delphi
> midas.dll. And the source code is available and for free.

I have this code. There is a catch, because part of the code assumes
units which are in the vglib sources, and those are not free.
(but which I purchased, 6 years ago or so)
> Is this useful for Free Pascal?
> http://www.vglib.com/link-4.html

It would allow you to create a TClientDataset clone. It will not help
with TBufDataset. It won't be easy to use cross-platform, because it 
has - partly - COM structures in it.

My plan - as time permits - is to let Joost finish the TBufDataset.
Then I will look at WST to create a transport layer.

I currently use WST as transport layer to transmit data between
a client and server, and it works as a charm.


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