During the January 20th TCU broadcast, I mentionned that you could attach an
IMAGE database to the same DBE using the WITH USER= parameter for the ATTACH
command.  Evan Rudderow called earlier this week to point out that this is
incorrect.  IMAGE/SQL does not permit the same database to be attached to the
same DBE more than once.  It is documented in the IMAGE/SQL administration
guide on page 4-4.
 
What I should have said (and was trying to explain), was that you can attach
the same IMAGE database to the same DBE using the WITH USER= parameter, as
long as the IMAGE databases are in different groups or different accounts.
 
Why would you want to do this?
 
There are many cases of which I am aware, where the same databases (name and
structure) is replicated in multiple groups.  As an example, a sales
application uses the SALEDB in group DB1994 for 1994 transactions and DB1995
for 1995 transactions and so on.  You get the drift.  The database name and
structure is the same, so that at ATTACH time, the OWNER,  (remember) would
always be SALEDB, by default.  You would get an error since the same tables
(datasets) would already exist for the OWNER SALEDB.  The way around this is
at attach time, you go like this:
 
SET SQLDBE SALESDBE
SET TURBODB SALEDB.DB1994
ATTACH WITH OWNER=DB1994
EXIT
 
SET SQLDBE SALESDBE
SETTURBODB SALEDB.DB1995
ATTACH WITH OWNER=DB1995
EXIT
 
You would then have very separate entities and could address data from
DB1994.INVOICES and DB1995.INVOICES with no problems.
 
At some point in the past, while discussing the problem of overloaded
datasets with several people, the idea of multiple attaches was put forward
with the idea that one could do different SPLITS on each attach.  This is
totally unworkable.  For overloaded datasets where the data is of the same
type, like CHAR, one can use views with subsets. If the data is if differing
type for different record type, you are out of luck.
 
 
Sorry for the confusion,
 
Kind regards,
 
Denys. . .