> Army wrote:
>
> >I've come across the following behavior with the Derby engine.
It seems
> >like a bug to me, but I thought I'd check to make sure it's
not "working
> >as designed" before filing a JIRA entry.
>
> >If I create a table with a large blob column (say 100K), and
then I try
> >to insert a CONCATENATED blob value into the table, where one
of the
> >blobs to be concatenated is larger than 32672 bytes, I get a
truncation
> >error, even though the blob column is large enough to hold the
value
> >without truncation.
>
>
> [ code, stack trace omitted]
>
> >This is where my uncertainty begins. It seems to me that, in
the above
> >reproduction, "the declared length" would be 100K and the
length of the
> >host variable would be 32700. In that case, since 32700 <
100K, this
> >should be a valid insertion. But since the variable is
rejected, either
> >1) I'm misinterpreting what the "declared length" is, or 2)
the declared
> >length is not being calculated correctly (it's being set to
32672 when
> >it _should_ be 100K).
>
>
>
> I think the issue/bug is that the contactenated operator is
resulting in
> a type of VARCHAR(32762) FOR BIT DATA, not BLOB. Or maybe the type
of
> the ? is mapped to VARCHAR(32762) FOR BIT DATA. I wonder what the
type
> of the ? parameter should be with your statement?
>
> >Note that this "checkHostVariable" method is called for Blobs,
but is
> >NOT called for Clobs. Thus, if I try to do the exact same
thing using
> >clobs instead of blobs (with characters instead of bytes, of
course),
> >everything works fine.
>
>
> The difference it there to match DB2's JCC driver. Basically
> checkHostVariable() is a check in additional to normalization.
> Column assignment always goes through normalization to ensure the
value
> is legitimate. Normalization rules allow truncation of pad
characters
> (0x20) when setting a value. DB2's JCC driver does not allow any
> truncation of binary values from a host variable.
>
> E.g.
>
> 'abc ' is valid for VARCHAR(3)
> 'abcd ' is not valid for VARCHAR(3)
>
> X'abcdef2020' is valid for VARCHAR(3) FOR BIT DATA (padded with two
> bytes) *except* when it is a host variable (set by a parameter
marker).
>
> Dan.
