Re: questions about views
- From: "Niall Litchfield" <niall.litchfield@xxxxxxxxx>
- To: skuhn@xxxxxxxxxxxx
- Date: Mon, 16 Jul 2007 12:22:20 +0100
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
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