Thanks for your response.

Yes, your point is well taken, assuming I understood it correctly, that the
term "surrogate" makes sense only when applied to a primary key. (I had said
in my OP that any field ending in "ID" was a surrogate key). When the same
field name appears in another table, it is no longer a surrogate key, but
simply the foreign key linking that table to the parent table. The fact is,
I did not know how else to say what I was trying to say. I didn't want to
say "autonumber", for the same reason, i.e., only the primary key is truly
autonumbered.

You are correct in your grasp of the relationships between Agreements,
Certs, and Policies. If Agreement 1000 has Cert 100, which in turn has
Policies A and B, and if Agreement 1000 also has Cert 200, then we do not
want Policy A to appear on Cert 200. Nor would we want any other Policy OF
THE SAME TYPE as Policy A to appear on Cert 200.

If things weren't already complicated enough, there is another level below
Agreements, Certs, and Policies, which is the Coverage Details. If I can
figure out how to manage the first three levels, the fourth will hopefully
not present any essential complications. Well..., except for the fact as
mentioned in another thread, that I will have to use one field to hold values
of different data types. I believe this means I will have to settle on one
data type, say Number, and then add another field to flag the value for what
it is really meant to be.

You are also correct about the Policy record not having direct access to the
AgreementID. Since the same Insured firm, with the same Policy, can enter
into more than one Agreement, the AgreementID cannot be built into the Policy
record.

The common fact about Agreements, Certs, and Policies, is the Insured firm.
I have added the InsuredID to the Certs table. When setting up a new Cert or
Certs for a new Agreement, the user should be presented with a list of
existing policies for the Insured; there should not be more than one of each
PolicyType. The user should be able to select policies for the new Cert, and
see them change from "available" to "already present on another Cert". Of
course for the Insured's very first Agreement, his Policies would have to be
added to the Policies table before they could be associated with any Cert.

Thanks Again,
OBP


"BruceM via AccessMonster.com" wrote:

It sounds as if you are on the right track in a lot of ways. You are
absolutely correct that a surrogate key does not guarantee uniqueness of
other data in the record. For that you need to use multi-field indexes
and/or form-level validation, as it seems you understand.

As a point of terminology, you may do better not to think of your linking
fields as surrogate keys. The combination of "real world" fields is what
guarantees a unique record, as you clearly understand. The surrogate key
just provides a one-field representation of the unique record, in the same
way an Employee # identifies the employee uniquely in a single field. The
linking fields, while they may not be "real" (i.e. they are arbitrary numbers)
derive their values from the surrogate key of the parent table, rather than
being surrogate keys themselves. In any case, they are not surrogate primary
keys.

As I understand, you could have for an Agreement the following:

AgreementID = 1000
Cert 100
Policy A
Policy B

Cert 200
Policy C
Policy D

You want to assure Policy A is not available for Cert 200 under the umbrella
of Agreement 1000, yes? If so, you do not have an index available to enforce
that rule (unless I am missing something) because the Policy record does not
have direct access to AgreementID. Instead, you need to use other
capabilities of Access to enforce that rule.

If the Policy is selected from a combo box on the subform bound to the
junction table, it should be possible to devise a query for the Row Source
that excludes policies already selected. I do not have time to devise an
example just now, and in any case I am not yet skilled enough at queries to
be sure I am pointing you in the right direction. That said, the logic would
probably be to select Policies from tblPolicy where PolicyID has not already
been used in the current Agreement record.

I wish I could be of more help. I have been watching this thread to see what
is suggested, as the problem interests me and I do not have a ready solution,
but as it has been a while since there have been any postings I am jumping in
to steer you away from an index-based solution, which I do not think you will
find for this situation. I expect the solution is SQL-based, particularly if
you are setting the Row Source for a combo box. A SQL string can be devised
in VBA to set the Row Source. If you wish to experiment further you could
try devising a query that returns all of the Policies used for an agreement.
This would probably involve joining the junction table to tblCert to
tblAgreement, restricting the tblAgreement record to just one. You could
hard-code the criteria for AgreementID for starters. That is, for a given
record make note of the number, then use that number as the AgreementID
criteria. You should be able to return a list of Policies used for that
Agreement. If you can do that you have made a good start.

Best suggestion other than that is to start a new thread. Perhaps the Forms
Programming group would be a good choice, or maybe the Queries group. A new
thread is likely to attract more attention to one that is several responses
deep.


oldblindpew wrote:
Not meaning to sound ungrateful, but the clear purpose of my original post
was to ask for suggestions on how to use the features and functions of Access
to implement certain specific business rules in my application. We seem to
have circumnavigated the barn only to arrive at the door. Folks were eager
to tell me I needed to use surrogate keys and to normalize my tables, but
when I ask about some of the basic ramifications of those choices, I often
get vague replies and shrugs of shoulders.

After drawing a blank here, I scabbed onto another recent thread entitled
"Multi-Field Primary Keys", which deals with this same subject, and got a
reply indicating there are indeed specific ways I can set up table
relationships using multi-field indexes that might prove helpful. The
response was perhaps a bit over my head, and this in itself is probably the
crux of the matter.

Designing an Access application is not easy, and there is only so much
people can do on a voluntary basis, from a distance. There are many ways to
go about it, and even experts sometimes disagree on the best approach.
Ultimately, designing an application is not something that can be done well
by someone "driving from the back seat". Please know that I appreciate your
interest and help. It appears I just need to continue slogging on in the
slow and painful business of gaining wisdom by trial and error.

With Sincere Thanks,
OldBlindPew

Sorry if I gave you a start, there. Yes, Access (and many other tools,
including Excel, paper/pencil, etc.) can be used to handle business rules
[quoted text clipped - 109 lines]

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