FreeTDS Development Group

["Lowden, James K" <LowdenJK AT bernstein.com>]

> From: Thomas A. Lowery
> Sent: Tuesday, November 16, 2004 3:28 PM
> 
> My attempts to use freebcp to populate a database table results in
> # Msg 20073, Level 2
> # Attempt to bulk-copy a NULL value into Server column which does not
accept NULL values.
> 
> There appears to be problem if any of the columns are null.
> 
> Here's a script to demo the problem.

Thomas, 

Oy.  Thanks for the script.  That was a serious bug.  

Please try the attached patch, already applied to CVS HEAD.  

The basic problem seemed to be in _bcp_read_hostfile:

        if (data_is_null) {
                bcpcol->bcp_column_data->null_column = 1;
               bcpcol->bcp_column_data->datalen = 0;
        } else {
+               bcpcol->bcp_column_data->null_column = 0;

The null_column flag of the column descriptor was getting set when the
data were null, but not reset when they weren't.  Adding the above line
fixed the problem.  

The patch does not apply to the 0.62.x release, because the problem
doesn't exist there. (I haven't tested it, but there's no 'null_column'
field to get wrong.)  

We used to encode the nullness of the data in its length.  That was
problematic, so now there's a separate field for nullness (although it
looks like 'null_data' might be a better name than 'null_column').  When
the field fell out of synch, your table started receiving nulls. 

Regards, 

--jkl

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Attachment: bcp.null_fix.diff
Description: bcp.null_fix.diff