[fpc-pascal]dbExpress with fpc

[Michael Van Canneyt]

On Fri, 13 Feb 2004 vkrish at vkrish.cjb.net wrote:

>
>
>
> > > > No. That is, FPC has no dbExpress components.
> > > Looks like dbExpress is written in C/C++ .
> >
> > IIRC dbExpress is sort of based on Midas. I doubt that dbExpress is legally
> > available for free use. I think you at least need a license for a Pro+
> > version of Delphi and thet covers you for deployment. None of the TDataSet
> > stuff was included in the Personal version last time I looked. Infact D7
> > Personal IDE will not let you load the Pro+ dataset packages. I know, I
> > looked into that as a matter of personal discovery ;-)
> hmm. I see dbExpress as a set of interfaces - thats it.
> I think you are free to implement them.

This is correct. You must implement a library which exposes this interface.

> btw, TDataSet is not part of dbExpress.

No. It's part of the VCL. It's available in FPC as well.

dbExpress has 2 parts:
- A VCL part - a TDataset Descendendent.
- A driver, which exposes a strictly defined interface.
The driver can be written in any language.

>
> I also looked at Qt's database classes and I see a strong resemblance to dbExpress's (including class and method names !)

I suspect that this is because Borland and Troll Tech cooperated on this
matter, and I would not be surprised if Troll Tech used Borland's design :-)

>
>
> > > FPC supports both COM and CORBA interfaces - right ?
> >
> > I wouldn't have thought so. Delphi does it via compiler magic.
> I think fpk told me so on #fpc .

An interface is a construct independent of COM or CORBA. It's just a set
of methods. Delphi does allow you to use COM methods transparantly via
interfaces. In principle, the same should be true for FPC.

Michael.