From: Gus Bjorklund [mailto:gus@progress.com] 
Sent: Thursday, 2 December 1999 3:53
To: peg@peg.com
Subject: Re: _Field 


on 12/1/99 9:51 AM, PEG Manager at pegmgr@emily.peg.com wrote:

>> Version 7.3E.
>> 
>> I need to provide a user interface to a function that would turn on/off
>> an audit trail for individual fields. Database triggers would perform
>> the audit function. It would certainly be nice if I could use one of the
>> fields in _Field as a flag indicating whether or not to create an audit
>> record on the write of the data. While looking at the fields in the
>> _Field table, I saw two fields that looked like good canidates. The
>> first is an integer called Fld-misc1 and the second is a character field
>> called Fld-misc2.
>> 
>> Are these two fields availabe for the Programmer's use? Is this a bad
>> idea? Does Progress provide any fields in _Field for the programmer's
>> use in later versions of Progress?
> 
> Putting something into the schema that the engine crew doesn't know
> about is a Very Bad Idea. Create my_field with key table-name, field-name
> and have all the field specific data you want.

Correct.

You are not allowed to use the schema contents for anything other than the
purpose they were designed for. The only legitimate programs that can write
to these tables are the Progress-supplied data dictionary and database
utilities. You should consider the contents to be read-only. I realize that
this is a strong statement but that's my story and I'm sticking to it.

If you start storing stuff in the these tables, you risk breaking something
or causing problems. The right combination of incorrect values could
possibly cause your database to become inaccessible, undumpable, and
unfixable.

Version 9 has fields called _User-misc in various schema tables (_file,
_field, _index, etc...). We put them there specifically for customers to use
for any purpose you wish.
-- 
regards,
gus
******************************************************************
Gus Bjorklund, Wizard, Progress Software Corporation, Bedford MA.
Purveyors of the finest rdbms on the third planet from the sun.

"All things considered, the invention of computers was a mistake".