Some basic questions

[418928]

Hi everybody,

I have some basic questions about Access. I hope you can give me a
hint:

-Can I define derive attributes? How? I think I can get a workaround
by defining a query that selects some attributes and computes
others... but I would need the derived attribute to be available
directly on the table.

-Can I define views in Access? Or, alternatively, use the result of a
query as an input for another query?

-Is it possible to make external unions? (i.e., unions of relations
with different attributes -completing with nulls if necessary).

-Is there any trick to enforce that two relations are mutually
exclusive?

Thanks in advance,

Sergio

 

[Guest]

See comments in-line.
--
Jerry Whittle, Microsoft Access MVP
Light. Strong. Cheap. Pick two. Keith Bontrager - Bicycle Builder.

Hi everybody,

I have some basic questions about Access. I hope you can give me a
hint:

-Can I define derive attributes? How? I think I can get a workaround
by defining a query that selects some attributes and computes
others... but I would need the derived attribute to be available
directly on the table.

Nope. This isn't Excel nor does Access support table-level triggers. It's
usually a very bad idea to store derived data anyway. Do it in a query, form,
or report as needed.

-Can I define views in Access? Or, alternatively, use the result of a
query as an input for another query?

Yes. Access stores named queries and you can use them as the record source
for other queries.

-Is it possible to make external unions? (i.e., unions of relations
with different attributes -completing with nulls if necessary).

Possibly using Union queries.

-Is there any trick to enforce that two relations are mutually
exclusive?

Don't know of one. Seems to me that would be caused be bad table
normalization or weird business rules. You might be able to use a validation
rule at table level.

 

[Susie DBA [MSFT]]

Jerry is full of crap

Access Data Projects support derived columns (computer columns) in
addition to triggers

MDB shouldn't be used by anyone-- for any reason