[lazarus] db components

[Michael Van Canneyt]

On Mon, 28 Jun 1999, Rick Dawson wrote:

> Has anyone started on db components yet? I have yet to get a working copy
> of the project yet so that I can really find out, so I thought I would ask.
> 
> What direction is it taking / would it take? I have been looking iodbc and
> unixodbc a bit, and have come across a few references about kde and gnome
> might be including iodbc, or a dirivative thereof, in the future.  The
> iodbc, is, I believe, supposed to be source compatible with MS's odbc spec. 
> 
> This is of prime importance to me, much more so than your debate over where
> to base your controls, in GTK or QT.  My job is to do 'database
> development', which I do in Delphi. I would like, very much for my delphi
> code to continue on into the Linux environment.

I am writing TDataset and descendents, compatible to the Delphi ones.
However, the TDAtaset stuff will not go in the Lazarus project, it will
go in the underlying FCL components; for the simple reasons that
1) They are not GUI/Toolkit dependent.
2) Everyone should benefit from them, not just the lazarus people.
So it will be part of the compiler suite.

I am quite busy with them, however I will not release anything until the code
works.

At the moment, three descendents of TDataset will be created:
- TMySQLQuery, TMySQLTable (to handle MySQL based databases, as a test case)
- TRecordset (To directly handle records stored in a file)
More can be added later (for instance TODBCDataset).

> 
> Since this is my area of experience, I am willing to devote some of my time
> to this part of the project, though it would probably only be a couple of
> hours a week. I am slow, but I think I can contribute. Besides, I have
> several problems with Delphi's implementation of TTable and TQuery, such as
> they don't implement the 'recno' property for SQL databases like they
> should. That would have been a tremendous help in my current project.

I am open to improvements of the TDelphi TDataset implementation.
I Do think that compatibility is important. Exprience shows that users ask 2 things:
1) Cross-platform independence
2) Borland compatibility.

I intend to give them both as much as possible.

Concerning iodbc, i think a TDataset descendent needs to be written for it:
TODBCDataset.

If we can manage to make generic 'TTAble' and 'TQuery' components, I will be happy,
but it is not on my priority list. Experience has shown that usually one develops
for one particular kind of database, so I think it is more useful to have descendent
objects that work specifically on one kind of database; the advantage is a distinct
speed gain.

But I have ideas about implementing generic TTable and TQuery components, and some kind
of BDE replacement, for easy configuration.

You're welcome to contact me and discuss what we can do.

Michael.