[fpc-pascal]Writing a highly portable database...

[Michael Van Canneyt]

On Thu, 19 Jul 2001, Alexander Stohr wrote:

> Hello dear FreePascal community,
>
> i am currently in research on possibilitys to implement
> a non comercial database with some 10 - 30 MB in size.
>
> The current trend in decision looks like it will be
> done with some Win32 or Linux based MySQL server to
> provide some common interface for general search in
> the database.
>
> But there should be furhter a user based access rights
> system that allows manipulation of this database.

You will have to implement that manually, i.e. set up a
system of users and access rights by yourself.

>
> For some nice reasons it is of high interest to have
> an offline reader and an offline editor for the two
> mentioned purposes.

Does 'offline' mean that you will not be directly connected to the MySQL
server ?

> This means this program should
> run at least on Linux and on Win32 platforms in Text
> and in Graphics mode.

This should not present any problems, I think. You can use
GTK for easy graphics, this is very portable, and there
exists meanwhile a lot of documentation for the pascal
port of GTK (see website)

>
> Can anyone tell me if such doing is feasible?
> Are there any libs around that will let me do such
> clients? (I would prefer single code for any purpose)
> Or does someone know about a system where this is
> already possible but doesnt raise any huge fees?

I don't know of any such system, except midas (from Borland)
which must be paid for. You'll have to implement this manually.

>
> I know FreePascal is portable to the desired targets.
> But i am not that sure if i know about the right
> collection of toolsets that let these clients
> perform synchronisation with the servers over an
> internet conncetion without coding any platform
> differently. Maybe an E-Mail interface would serve
> here or any other protocoll, maybe several of them.

To answer your question, more information is needed; In principle
what you ask can be done using Free Pascal, but the implementation
of the synchronization is _not_ easy. This is difficult anyhow, and
this difficulty is not tied to FPC, but more of a principal nature.

In your case I would recommend always use a local mysql engine,
(the memory footprint is low anyhow) and run a synchronization
of the databases when going online. (but this may be a problem)

>
> The gui or textmode toolkit should be of a rather
> universal type as well, so that there will be
> possibilities to integrate i.e. country maps or
> other visualisation modules into the project on
> respective demand (of course less likely for the
> textmode version, will apply conditional defines).

This should be no problem using GTK for the graphics mode.

>
> The thing is i dont want to spent too much time but
> want to rely on a good amount of tested and prooven
> to be good code that finally just does what i want.

Don't we all want that ? ;)

Michael.