Beefy Boxes and Bandwidth Generously Provided by pair Networks
Syntactic Confectionery Delight

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
This is going to sound crazy, I know, but I have a feeling DBI is actually paying some kind of attention to the internal type of the presented variables.

During diagnosis, I tried to abstract the variable away into an array, which would make a copy and theoretically de-taint the orginal scalar. Then, a few things worked, surprisingly:
my $foo = ''.$key_value; my $foo = "$key_value"; my $foo = eval($dbh->quote($key_value)); # Desperation
Also, priming the query with some stupid data did the trick too:
Now it just occured to me that the data in $key_value leading up to the call that failed was strictly numeric, except when either a) the code was literally converted to a scalar, or b) enquoted, to force stringification.

Now, the question is, what does this mean?

My busted test case, which I'm curious to see reproduced, is:
my $sth = $dbh->prepare(" INSERT INTO web_sessions_aux (wsa_id, wsa_type, wsa_key, wsa_value) VALUES (?,?,?,?)", {}); my $rv = $sth->execute("2012","CRS","crs_search_index",1) && $sth->execute("2012","CRS","crs_search_criteria","S") ; $sth->finish();
Note the numeric in the fourth column (CHAR). Why would this matter?

Update: Solved!
It would seem to be a problem in DBD::mysql which checks the "type" of the scalar being passed to the execute call. From dbdimp.c:
if (!ph->type) { ph->type = SvNIOK(ph->value) ? SQL_INTEGER : SQL_VARCHAR; }
You can see here that if the placeholder type is not set, it uses the Perl internal representation as a hint. Unfortunately, once assigned, this is never checked again. To clear up the problem, I just assigned straight to SQL_INTEGER and everything is A-OK.

In reply to Re^2: DBD::mysql Unusual Behavior by tadman
in thread DBD::mysql Unusual Behavior by tadman

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, 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, 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.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others chanting in the Monastery: (7)
    As of 2020-12-03 16:44 GMT
    Find Nodes?
      Voting Booth?
      How often do you use taint mode?

      Results (57 votes). Check out past polls.