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PowerTree for DOS

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  • PowerTree for DOS

    Could give some information about the way to use PowerTree (for dos)with file which have variable length record (like CSV file)
    Thanks for your help.
    Regards

    Philippe

  • #2
    All versions of PowerTREE work the same way - you pass a "key" string and a numeric "record number" value to PowerTREE and it stores the information. PowerTREE does nothing to the "record number" other than store and retrieve the value associated with a key.

    Therefore, what this value represents is up to you, the programmer. It could be a record number, or it could be a byte position within a file.

    With this in mind, indexing a file with variable-length records is simple - simply specify the byte (SEEK) location of the beginning of each "record" in the file as the "record number" value for PowerTREE.

    This makes it possible to index such a file with either binary or sequential file access, and use the SEEK function to retrieve the "record" location as you move through the file.


    -------------
    Lance
    PowerBASIC Support
    mailto:[email protected][email protected]</A>
    Lance
    mailto:[email protected]

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    • #3
      I presented some concepts in my article, "Database Indexing" which appeared in the July, 1995 issue of "BASICally Speaking." While I used the (free) "BT" index manager for the sample code, the text covers "index only" managers (such as PowerTree) in a pretty generic fashion.

      Reprints may be ordered ($4.00 US) from the publisher's web site http://www.infoms.com

      (I have no financial interest in reprint or subscription sales).


      -------------
      Michael Mattias
      Racine WI USA
      [email protected]
      Michael Mattias
      Tal Systems Inc. (retired)
      Racine WI USA
      [email protected]
      http://www.talsystems.com

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