You could use Digest::MD5 but that only operates on one string. In general, an object is a blessed reference to a compound data structure which doesn't automatically fit. So the real challenge is to figure out a unique way to convert the data structure to a single string that can be converted to MD5. Data::Dumper won't can guarantee a unique key ordering (see reply below from tinita). , so you'd need to sort the structure by hash key before delimiting, although arrays should be used in existing order ( $; = ASCI(19), non-printing, is also a useful delimiter for printable data ).

The only thing that occurs to me though is that fingerprinting the whole object shouldn't be necessary - it should be sufficient to fingerprint an ordered, delimited concatenation of selected instance fields. It is more usual (though not necessarily mandatory) for this to be the primary key in the logical data model rather than some bulk data field.

Update: You could also consider storing the MD5 in the database, setting a UNIQUE constraint on some selection of fields and letting the database deal with the problem.

__________________________________________________________________________________

^M Free your mind!

In reply to Re: How to make a fingerprint from an Object by Moron
in thread How to make a fingerprint from an Object by jeanluca

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.