Re: UNION CASTING .

there are simple views and complex views which accounts for the differences you have observed.

"Aparna" <bliss_is_ignorance_at_hotmail.com> wrote in message news:3ae9755c.0_at_news.tm.net.my...
> oh one more though... we cannot perform DML's on views based on unions...
> the DML's can be performed only on the tables....
>
> regards,
> aparna
>
> "Steve Long" <steven.long_at_erols.com> wrote in message
> news:9cbof3$oln$1_at_bob.news.rcn.net...
> > my hunch is that the constraints are applied at the table level (as they
> > should be) rather than the view level. where did you create a not null
> > contraint on the "view column" ? if you constructed something similar
 as
 an
> > updateable view, a null value would result in a violation of the table
> > constraint. the dictionary is correct.
> >
> > "Maze Control - Terminal 23315 - Central 2" <trw-sinterface_at_pluto.gwy>
 wrote
> > in message news:0PbG6.12036$_W2.12062_at_news.indigo.ie...
> > > Can anyone help me with this ?
> > >
> > > Try the following SQL.
> > > --create table table1 (col1 integer not null)
> > > --create table table2 (col1 integer not null)
> > > --create view view1 as select * from table1
> > > ---union all select * from table2
> > >
> > >
> > >
> > > if you then do select column_name,nullable from user_tab_columns where
> > > table_name='VIEW1'
> > > the result is that col1 can contain nulls, which is incorrect.
> > >
> > > Try it on your own system - happens at least on Dynix and Win2000.
 V817
> > >
> > > Does anyone know how to hack the data dictionary to force this to be
> > > not-null ? (i.e. correct )
> > >
> > > Creating another view on top of this (AS SELECT COL1 from VIEW1 WHERE
 COL1
> > > is NOT NULL )
> > > does not work .
> > >
> > > This is a small case of a much larger production issue. The view
 cannot
 be
> > > replaced with a table.
> > > TIA !
> > >
> > >
> > >
> >
> >
>
>
Received on Fri Apr 27 2001 - 09:04:57 CDT