CDX Format

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GeoffBarnard
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CDX Format

Post by GeoffBarnard » Mon Nov 11, 2013 3:58 pm

Hello,

I'm new here. Just been checking out CDX indexes in samples, but format of CDX seems to be different to what I'm used to. The ones I've used, and have a number of utilities for handling, have all the tags detailed in the header, followed by all the data. The HMG variant I'm looking at shows a list of the tag names in the header, followed by the full detail of the first key, then the data for that key, then the full detail for the second key, then data, etc.

Are there two different formats for CDX files?

Geoff

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esgici
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Post by esgici » Mon Nov 11, 2013 4:16 pm

GeoffBarnard wrote:Hello,

I'm new here. Just been checking out CDX indexes in samples, but format of CDX seems to be different to what I'm used to. The ones I've used, and have a number of utilities for handling, have all the tags detailed in the header, followed by all the data. The HMG variant I'm looking at shows a list of the tag names in the header, followed by the full detail of the first key, then the data for that key, then the full detail for the second key, then data, etc.

Are there two different formats for CDX files?

Geoff
Hello Geoff

Welcome aboard, greetings from Turkiye :)

In summary, internal structure of index file no matter for me, in general, if it works correct no problem.

If you want to use CDX file(s) built in any other tools by Harbour compiled application, may be some incompatibilities.

I didn't see any other problem with CDX files.

Does possible a little sample ?

Happy HMG :D
Viva INTERNATIONAL HMG :D

Javier Tovar
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Post by Javier Tovar » Mon Nov 11, 2013 5:00 pm

Hola Geoff

No se a que te refieres exactamente, podrias hacer una muestra minima completa para poder entender.

Gracias

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Hi Geoff

Not exactly what you mean, you could make a complete minimum sample to understand.

thanks

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Post by dhaine_adp » Mon Nov 11, 2013 7:07 pm

Hi Geoff,

Welcome aboard to HMG. If you're really interested on low level/custom handling of CDX perhaps downloading Harbour (Hb) source code will give you a deeper insight not only with CDX but all RDDs' supported by Hb. HMG is a graphics library created by Mr. Roberto Lopez. However what connects between the GUI and record handling lies with Harbour RDDs', contribs (contributions) and 3rd party contributions. You can find the source and binaries from here:
The only exception with Harbour DFBCDX is that you can't mix HB DBFCDX driver from another application that uses a different DBFCDX. But within Harbour, we haven't encountered any problem so far.

Assuming that you unpacked the Harbour source on this directory: C:\harbour\core-master\src\rdd -- Your will find all the source codes and function wrappers as you traverse and trace the files and source codes in C. Please take your time skimming through the source codes and don't forget to read the file changelog.txt (You can search this file too, for more info and development history of Habour including RDDs' and DBFCDX).

If you feel that you need more information, the best approach is to address your concern directly to the Harbour Developers at: http://harbour.github.io/" onclick="window.open(this.href);return false; From that Websites Menu, hover your mouse to Development, then click Report Issues.

Regards,

Danny
Regards,

Danny
Manila, Philippines

GeoffBarnard
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Post by GeoffBarnard » Tue Nov 12, 2013 12:02 am

Hello,

Thanks for messages.

OK, it may be problem with Harbour, not with HMG as such.

Yes, I accept that.

Looking elsewhere, I see some notes that MS may have changed format of .CDX (compound indexes) with intro of VFPro8. My existing systems may be using previous format, I'll have to see what I can do about that.

For my main developments (still DOS based) I'm using Codebase (Sequiter) and C. Still maintaining one BIG system, plus various personal processes. The big warehouse system uses .CDX, various big files using multiple tags.

I was thinking I might be able to use HMG to introduce some windows processes, accessing the main data files, but if indexes are different then this cannot be! I'll do some more testing, but it's possible .CDX with single tag may be OK, problem just with multiple tags.

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Post by esgici » Tue Nov 12, 2013 12:37 am

Hello Geoff
GeoffBarnard wrote: ...
I was thinking I might be able to use HMG to introduce some windows processes,..
You are the correct place 8-)
accessing the main data files, but if indexes are different then this cannot be!
No ! Please don't panic !

If you are planning share same data and index files between DOS based and 32/64 bit applications, I'm afraid that you have to be ready to bigger problems :(

Otherwise, if each application will use their files self-contained, should be no problem; simply you need build new CDX files once.

<hmg>\SAMPLES\Controls\EditBox\EDIT.EXTENDED\demo.prg ( OpenTable() procedure ) may give you some ideas on managing CDX files. :idea:

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Post by serge_girard » Tue Nov 12, 2013 9:20 am

Hello Geoff,

Welcome from Belgium!

I started exactly one year ago with converting old clippers to HMG and with the help of this forum I now have
3 large applications up and running in production.

What I mean is: for any possible problem there will be a nice HMG solution !

Greetings, Serge

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Post by Rathinagiri » Tue Nov 12, 2013 10:49 am

Hearty welcome Geoff.
I started exactly one year ago with converting old clippers to HMG and with the help of this forum I now have
3 large applications up and running in production.
Wow! That is so great Serge.
East or West HMG is the Best.
South or North HMG is worth.
...the possibilities are endless.

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Post by serge_girard » Tue Nov 12, 2013 1:40 pm

Thank you Rathinagiri. It all would be impossible without HMG and all your good examples!

Serge

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Post by dhaine_adp » Tue Nov 12, 2013 5:21 pm

Hi Geoff,
For my main developments (still DOS based) I'm using Codebase (Sequiter) and C. Still maintaining one BIG system, plus various personal processes. The big warehouse system uses .CDX, various big files using multiple tags.

I was thinking I might be able to use HMG to introduce some windows processes, accessing the main data files, but if indexes are different then this cannot be! I'll do some more testing, but it's possible .CDX with single tag may be OK, problem just with multiple tags.
Map out your tables or database and begin converting those at the bottom. That would be a long hard work man but definitely it can be done. The good thing is that you can preserved your database structure and all data in it.

Somewhere along, you are always welcome in the forum. W'eve all came from the same place where you at now.

-Danny
Regards,

Danny
Manila, Philippines

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