Re: Nulls in program described file

[Simon Coulter <shc@xxxxxxxxxxxxxxxxx>]

On 10/07/2004, at 8:41 AM, Buck Calabro wrote:

> The help says that ALWNULL works with externally described files.  I
> don't see any equivalent for program described files...

There isn't. How could there be? A program-described file is one big 
field. How would the database know that the 12 bytes at offset 103 is 
really a null-capable field? How could it set the null-byte map 
correctly?

Because the null-byte map uses 1 byte per field in the file (and is set 
to 0 for not null and 1 for null) there would only be 1 null indicator 
reflecting the state for the entire record (since a record in a 
program-described file is a single field).

The file you are reading must be externally-described because you 
cannot create a program-described file with null-capability. You have 
to use DDS to define null-capability and all DDS defined files are 
externally-described by definition.

Do you just want to process an externally-described file with nulls AS 
IF it were program-described? If so why? What are you trying to 
achieve? There is probably an alternative that will work if you can 
explain what you want to do.

You could do this by creating your own UFCB and building the null maps 
yourself but you're probably looking for something easier.

Regards,
Simon Coulter.
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