Re: SQL question: something analogous to a multi-format logical . . .

[Vern Hamberg <vhamberg@xxxxxxxxxxx>]

James

I'll make a very general suggestion, then more pointedly address you 
question, where you have the same format.

I've always recommended using UNION SELECTs - if all the files have the 
same format, then just do the UNIONs - if you need some identifier for 
each (think format ID in I-specs, right?), then add a character literal 
in front of each that handles the identification. If there are different 
formats, it gets a little more complicated, but the idea is to use some 
format ID, then concatenate the rest of the fields you need into a 
character field, then move (eval) that to a data structure with the 
appropriate subfields.

Say you have LIB1/MYFILE and LIB2/MYFILE. Then you have options

If you have something in each instance that identifies it, or you don't 
care about that -

SELECT * FROM LIB1/MYFILE
UNION
SELECT * FROM LIB2/MYFILE

If you need to distinguish each library's data -

SELECT 'LIB1', MYFILE.* FROM LIB1/MYFILE
UNION
SELECT 'LIB2', MYFILE.* FROM LIB2/MYFILE

You don't have multiple formats, so I'll skip that one.   ;-)

There are some limits to the number of UNION SELECTs - 
release-dependent, IIRC.

HTH
Vern

James H. H. Lampert wrote:
> Is there something that can be done in SQL, that would effectively make
> a bunch of instances of the same file, in several different libraries,
> look like a single file?
>
> Case in point: a user enrollment file, associated with an instance of an
> application.
>
> --
> JHHL
>
>