[plt-scheme] Need some advices for Database

From: Stephen De Gabrielle (stephen at degabrielle.name)
Date: Wed Mar 12 07:27:09 EDT 2008

Hi, here's the quick version;

write and read work, if you are happy to use hash tables for your data

  ;; save-hash-table  : hash-table file ->
  (define (save-dict dict file)
    (print-hash-table #t)
    (call-with-output-file file
      (lambda (port)
        (write dict port)) 'truncate/replace)

  ;; load-hash-table  : file -> hash-table
  (define (load-dict file)
    (call-with-input-file file
      (lambda (port)
        (read port)))

I think I've been nesting my hash tables with no problems. (ie a value
can be another hash-table)

I'm pretty sure you can use struct's in the same way.

(I can't make sense of your use of class%)

if you really want an xls compatible format, (or wish to use a rdbms),
there are libraries in planet that help see
http://planet.plt-scheme.org/ - eg csv.plt: Comma-Separated Value
(CSV) Utilities in Scheme



On Wed, Mar 12, 2008 at 10:48 AM, Ziboon <ziboon at gmail.com> wrote:
> hi all,
> I'm
> I am beginning in scheme language, I try to create a small program, it's a agenda / contact, I want to save & load my data  when I execute my prog.
> I need two advices :
> 1) what is the best way to make a simple database with scheme?
>  I start to make class% and define link into different class.
> 2) But the real problem is how to load & save data (in xls for example) , what is the best simple method ?
> Maybe this way "(open-output-file filename)" ?
> thanks
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Stephen De Gabrielle
s.degabrielle at ucl.ac.uk
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