From: Achilleus Mantzios <achill@matrix.gatewaynet.com>
To: David Klugmann <dklugmann@hotmail.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: View unique rowid
Date: Wed, 1 Jun 2005 18:21:53 +0300 (EEST)
Message-ID: <Pine.LNX.4.44.0506011805190.16893-100000@matrix.gatewaynet.com> (raw)
In-Reply-To: <BAY104-F738FF8AD0C05D867CF6D5B2050@phx.gbl>
O David Klugmann Ýãñáøå óôéò 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)
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index scan if your
> joining column's datatypes do not match
>
--
-Achilleus
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To: pgsql-sql@postgresql.org
Cc: achill@matrix.gatewaynet.com, dklugmann@hotmail.com
Subject: Re: View unique rowid
In-Reply-To: <Pine.LNX.4.44.0506011805190.16893-100000@matrix.gatewaynet.com>
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