O David Klugmann έγραψε στις Jun 1, 2005 :
>
> Hi
> Is it possible to refer to a unique row identifier on a view ?
>
> I have the following view but in a subsequent select I need to refer to
> each row's unique identifier and I know oid's are not valid for a view.
Provided your ids are 4 bytes long, you could try to build an artificial
id as
>
> create view persontransit
> as
> select personid, planet, name as aspectname, position as planetposition,
SELECT personid::int8 as viewid,....
> position+angle as transitposition
> from personplanet, aspect
> union
> select personid, planet, name as aspectname, position as planetposition,
SELECT X'1'::int8<<32 | personid::int8 as viewid...
> position-angle as transitposition
> from personplanet, aspect
> where name != 'OPPOSITION';
>
> Many thanks
>
> David
>
that way the viewid is unique, + you know which part of the view
it represents by masking on the 33th bit (4294967296),
while you can get the actual personid by masking with
X'FFFFFFFF' (4294967295)
>
>
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-Achilleus
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