Re: Are level checks still useful?

[CRPence <CRPbottle@xxxxxxxxx>]

On 07 Nov 2012 18:17, Nathan Andelin wrote:
> I'm not settled on this technique, I just put it out for thought. It
> appears that you can add table columns without "agonizing" about
> "recompiling the world".

  It seems to me that it would be much easier to just implement logical 
independence so that only the programs that need to use the new column 
would be changed and recompiled; changed to use the new LF which now 
includes the new column added to the PF.  All other programs would 
remain unchanged, continuing to use their unchanged LF [an LF which was 
never updated to include the new column irrespective of PF changed by 
ALTER TABLE, CHGPF SRCFILE(named), or even when the PF was re-created 
such that the LF had also been re-created from source].  That works 
because all of the LFs would have been defined with explicit fields 
instead of merely inheriting the record format from the PFILE 
specification, which ensures the logical independence from the physical 
changes.

  Thus total freedom from the alluded "agonizing" is achieved for the 
minor cost of some extra logical files to manage, while maintaining any 
protection provided from level checking, and as Charles stated... also 
with the great benefit of no changes to the other programs and their 
LF(s) which effectively eliminates the need for re-testing those other 
programs.

  FWiW with regard to the subject, my opinion is that Level Checking is 
only as useful as a helmet might be for riding.  In either case there is 
no value provided whenever no situation arose such that the protection 
offered would be required.  Anyone who can correctly predict that no 
such situation will arise has no need for any assistance from a 
preventive.  Also FWiW, failing to ensure a change to a record format 
effects an actual change to the Level Identifier [it is just a hash] 
when there has been a change [that could cause data issues], might be 
considered similar to failing to ensure a helmet is properly fastened; 
i.e. the best possible protection may not be afforded even though by 
appearances, the preventive seems enabled.