Re^2: DBI bind_param

in reply to Re: DBI bind_param_inout trick
in thread DBI bind_param_inout trick

Looks like a bug in DBD::ODBC. Parameters are bound initially in ODBC at bind time and if they change at execute time they have to be rebound ODBC-wise. The following code is what tests whether a parameter needs to be rebound:

if (SvTYPE(phs->sv) != phs->sv_type /* has the type changed? */
   || (SvOK(phs->sv) && !SvPOK(phs->sv)) /* is there still a string? *
+/
   || SvPVX(phs->sv) != phs->sv_buf /* has the string buffer moved? */
                ) {
                if (!rebind_param(sth, imp_sth, imp_dbh, phs))
                    croak("Can't rebind placeholder %s", phs->name);
               }
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Trouble is I didn't write that code which attempts to rebind the parameter ODBC-wise and although I understand the first and last test in the if condition the comment next to "(SvOK(phs->sv) && !SvPOK(phs->sv))" does not seem to agree with the code. I wonder what the original author meant. It also does not cater for a parameter being undef then a string.

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Re^3: DBI bind_param_inout trick by mje (Curate) on Sep 05, 2012 at 09:22 UTC
This is now fixed in 1.40_1. There is a small discussion on the dbi-dev mailing list if you are interested.	[reply]
Re^4: DBI bind_param_inout trick by runrig (Abbot) on Sep 05, 2012 at 16:52 UTC
Awesome! I expected this to not be supported in some DBDs, but if it fleshes out bugs where it is supposed to be supported, then it's done more than originally intended!	[reply]
Re^5: DBI bind_param_inout trick by mje (Curate) on Sep 06, 2012 at 08:03 UTC
Thanks for the example runrig. The problem was fairly specific in that it only went wrong it you called bind_param_inout with undef values initially then changed them to strings shorter than 28 characters. However, it was certainly a bug and I was a little surprised no one has hit it before.	[reply]

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