On Sun, Jul 13, 2003 at 03:27:11PM -0700, Hilmar Lapp wrote:
>
> On Sunday, July 13, 2003, at 12:19 PM, Tim Bunce wrote:
>
> >>I also tried against the real table (instead of the synonym to it) and
> >>then even wrapping the parameter in NVL() works just fine (!).
> >
> >Good.
> >
>
> Hi Tim, thanks for your response. To give another glimpse on how this
> story unfolds, I'm now scrapping my second iteration to solve this
> problem, which was to edit the generated update statement to replace
> the synonym with the real fully qualified USER.TABLE (the dictionary
> view ALL_SYNONYMS let's you figure out that piece). I then added {
> ora_type=>ORA_CLOB, ora_field=>'SEQ' } to every $sth->bind_param() call
> for that specific statement when the value is longer than 4000 chars.
> (that piece of code doesn't know about the order of columns in the
> statement.)
>
> The problem with this approach is that it works fine if the first bind
> for that NVL-wrapped LOB column gets passed the hash of type
> parameters, but it doesn't if the first one does not pass those
> parameters (because the value to be bound happens to be shorter than
> 4000 chars). I was back then at the ORA-01461 exception.
>
> Apparently subsequently (after the first execution - or first bind for
> that column?) passed type parameters are ignored if the statement
> handle is the same as before.
Yes. Bind param attributes are 'sticky'.
> Is this a feature or a bug :-)
Feature.
> I can imagine it's a constraint imposed
> by OCI, but I don't know. At any rate, my humble suggestion is to
> mention this in the documentation as I was really unprepared for that
> and it took me a long night to figure out what was going on.
The bind_param docs do say:
: The data type for a placeholder cannot be changed after the first
: C<bind_param> call. However, it can be left unspecified, in which
: case it defaults to the previous value.
but I'll make it more clear that the whole \%attr param is sticky
and drivers may ignore \%attr after the first call:
: The data type for a placeholder cannot be changed after the first
: C<bind_param> call. In fact the whole \%attr parameter is 'sticky'
: in the sense that a driver only needs to consider the \%attr parameter
: for the first call, for a given $sth and parameter. After that the
: driver may ignore the \%attr parameter for that placeholder.
Tim.
