RE: questions about views
- From: "Michael Rosenblum" <mrosenblum@xxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 16 Jul 2007 10:16:18 -0400
To be precise, there are some cases when synthetic primary key on the view
is needed. Example:
* there is a complex view with INSTEAD-OF triggers
* I want to manipulate that view in the app built via JDev using
ADF-BC
As far as I understood, ADF-BC must know a primary key column to maintain
modified information in the cache. As a result, I have to define a primary
key column and tell it to my JDev team for every view-based entity they
build.
Regards,
Michael Rosenblum
Dulcian Inc
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Niall Litchfield
Sent: Monday, July 16, 2007 7:22 AM
To: skuhn@xxxxxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: questions about views
Hi Stefan
comments inline
On 7/16/07, Stefan Kuhn <skuhn@xxxxxxxxxxxx> wrote:
Hi all,
I am new to oracle and views and I have two questions:
1. How can I add a new integer columns, which can simply start with 1 and
count, as a primary key to a view I. e. i have have the select query, which
is fine, and I just want the new column as the first column in the table.
It doesn't really make sense to consider a primary key for a view. A view
is, simplifying a bit, a stored query, primary keys apply to the base
tables, not select statements. If you want a pseudo column that increments
by one each time then you can use the construct rownum. Eg
create or replace view rownum_eg
as
select rownum fake_pk,ename,deptno
from emp
order by deptno,ename;
2. Can I put two queries in one view? I have a table, which has two
columns,
the values of these columns are supposed to go in one column. No problem to
select one of them, but I have no idea how to do it with both columns.
Thanks for help
Stefan
In principle anything you can select can be made into a view (though this is
not always wise). I'm reading this question as how to concatenate two
columns. The concatenation operator in Oracle is || so you might adapt the
above example to
create or replace view concat_eg
as
select rownum fake_pk,ename||' Dept: '||to_char(deptno) Name_and_Number
from emp
order by deptno,ename;
--
Niall Litchfield
Oracle DBA
http://www.orawin.info
Other related posts:
