Re: dbase

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Hi Daniel,

Daniel Berstein Zimmermann wrote:

> Hi Marcel, I'm also interested in databases. I have some expirience
> with Clipper 5.2 and other Xbase laguages, which use the standard
> .dbf file. By now I'm coding some functions that read and write
> .dbf files, and also some utility function for databases: a browse()
> function (like browse or dbedit of clipper, based in my menu engine)
> and some get() function with "pict" capability, and of course an
> indexing system.

Thats the point.......

> For what I've telled you I have an idea (even some functions are
> ready) of what to code, but for indexing (I expect to make it
> compatible to Dbase's NDX format or Clipper's NTX format) I just
> don't know where to start.

I had the same problem. I ask my girl friend where to start. She
said: "In the middle." So I did. (No dirty joke gentlemen) I found a
study book of Wirth "Data structures" and studied the B+tree section
and started to code an tree insert, delete and search function. Made
my own file structure and so on. I worked back and forth. I can tell
you, If you've seen one you've seen them all. It's one principal
easy to understand but huge to code.

> If you have some specs of this formats I would be very thankful.

I don't have have spec's of NDX, NTX format and I can't find
information about it on the net.

> I will post these function when they get more
> complete. I think it's great we could share our codes,

Yes, great I look forward to it.
When I get my B+tree code stabilized and it does what it has to do I
put it on the listserver.

> but some
> codes posted in the listserver require tons of patience to
> understand their mechanics. I spend lots of time translating to

You are right. It takes me also lots of time to study others code.

> English (the comments, the function names and the variable names)
> so they could be easily understood by everyone (hope), and be a
> source of ideas (hope too) >for all.

Thanks Daniel for your reply. Keep on coding ....

A tip .... David Gay wrote some interesting indexing code to link two
databases with common fields. I'm now studying this code and try to
use it for an applycation I have in mind.

Marcel Kollenaar
M.Kollenaar at slo.nl
The Netherlands

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