Using Views to Create Views with outer joins

Using Views to Create Views with outer joins

Post by Bob Rege » Fri, 03 Feb 1995 15:09:48



Does anyone know if it's possible to create a view from two
other
views using an outer join? So far, it doesn't seem to work. The

result set is the same as an inner join.
I was going crazy trying to figure out what was happening in
my datawindows.
To make things simpler to understand, I created 2 simple tables
with 3 columns each. I created a view from these tables, with
an
outer join and the result set was as expected.
I then created 2 views, one from each of my original 2 tables
that contained all columns from the original tables.
In other words, each view was identical to the table
it was derived from.
When I then created a view from these views with an OJ, the
result set was not correct.
Is this technically not possible, due to the way views work, or
have I discovered yet another bug? Using Watcom 4.0

TIA

--bob

 
 
 

Using Views to Create Views with outer joins

Post by Andrew Pearmu » Thu, 09 Feb 1995 04:20:48



Quote:Regent) writes:

> Does anyone know if it's possible to create a view from two
> other
> views using an outer join? So far, it doesn't seem to work.

I spent ages over this one. Powersoft Tech Support first told me to get the
latest watcom - (5 upgrades and as many weeks later, still didn't work)

Powersoft Tech Support now tell me that I shouldn't be trying to do it at
all; that what I am doing is the wrong way of using a view.
I still hold that I had legitimate reasons to use a view that did (if then
else) statements to get computed totals for a table, and then doing a left
outer join from the table onto that view to get calculated results where
applicable.

I gave up in the end, and now maintain running total fields in the table in
question - yeuch!
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1. Help: Updates Within an Outer Joined View

You cannot update tables when the data source of your datawindow comes
from multple tables.  It is because all update flag of your datawindow
columns is set to false initially.  I think you have to modify the
update flag.  Each time you issue update function PB will only update
one table.  So if your datawindow comes from two tables, you must
issue two update function for these tables individually and the update
flag of all columns of another table should be set to false.

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