Evaluating opinions - FilePro Error Messages

[Nancy Palmquist]

Bill Vermillion wrote:
> 
> On Thu, Jun 03, 2004 at 06:17:27PM -0400, Fairlight thus spoke:
> 
> > On Thu, Jun 03, 2004 at 04:55:26PM -0400, Jay Ashworth, the
> > prominent pundit, witicized:
> 
> > > On Thu, Jun 03, 2004 at 04:41:30PM -0400, Nancy Palmquist wrote:
> > > > Fairlight wrote:
> 
> > > > > Tecnically yes. However, how hard would it be to actually
> > > > > put code in fP that prevents one from modifying the
> > > > > key field(s) of the lookup index to prevent people
> > > > > from making the mistake at all? I shouldn't think very
> > > > > difficult, since it knows exactly what fields it's
> > > > > dealing with.
> 
> > > > Never support this in a million years. After I attach to a
> > > > record with a lookup, why should it not allow me to change
> > > > a KEY field any way I want. How does it know what I will do
> > > > next? You are asking it to change a fundemental feature, to
> > > > protect bad logic.
> 
> > > I concur entirely.  That's not the proper solution.
> 
> > I was thinking off the cuff. After Nancy went into it, I could
> > see that it was a bad solution. I was trying to think of a
> > way to prevent the programmer from shooting themselves in the
> > foot--especially ones just learning.
> 
> I have a question so I can understand a bit better. When it was
> mentioned "after I attach to a record with a lookuup, why should it
> not allow me to change a KEY field any way I want".
> 
> Does this mean the key field in the looked up record, or the key
> field in the record from which the lookup is being made.
> 
> If the latter that violates one of Codd's 12 Rules.  Modifying a
> key that has references to that key loses any referential integrity
> and if the looked up record has any other references to it, which
> might reference the first you lose your integrity.

What if I am trying to JOIN two accounts that were added incorrectly on
two seperate numbers.  I am trying to change the account number of one
to the number I want to include it in.

What if I have an index on an area code and I am trying to make a change
for new area codes?

What if I have an index on a date and want to change it to another date?

What if I have an index on the customer name and they change the name or
it was misspelled?

I could go on.

Nancy

> 
> I've written code in the far past to ensure that keys are never
> modified if anything that uses those keys is extant in the database
> after being called in to find out what data the client knew was
> there could not be found.   That was to make FP act more like a
> relational database.
> 
> Bill
> 
> --
> Bill Vermillion - bv @ wjv . com
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-- 
Nancy Palmquist 
Virtual Software Systems
PHONE: (412) 835-9417			Web site:  http://www.vss3.com