Update instead rules on Views

Hello,

It seems that I have a fundamental misunderstanding how views work.

See the following example:

--- snip snap ---

CREATE TABLE realdata (index int, data varchar, obsolete int);

COPY realdata FROM STDIN;
1 hallo \N
2 test \N
3 blubb \N
\.

-- The obsolete row is a row that is now to be calculated on the
-- fly. In our real data, this is to be a nested select, but random()
-- works for this example as well.
CREATE VIEW testview AS
SELECT index, data, (random()*99)::int from realdata;

-- But to remain compatibility with old apps, we also need to manage
-- updates to the view, which are to be rewritten as follows:
CREATE RULE testview_update_rule
AS ON UPDATE TO testview DO INSTEAD
UPDATE realdata SET
index = NEW.index,
data = NEW.data,
obsolete=NULL
;

--- snip snap ---

But now, when we issue an

UPDATE testview SET data='nono' WHERE index=1;

we get the result

UPDATE 3

So it updated _all_ of the rows instead of the qualified rows (WHERE index=1).
SELECT * FROM realdata;
index | data | obsolete
-------+------+----------
1 | nono |
1 | nono |
1 | nono |

But the documentation states: (rules-update.html):

| No qualification but INSTEAD
|
| the query tree from the rule action with the original query
| tree's qualification added

I read this that the original qualification (WHERE index=1) is applied
to the rule, resulting in a transformed query equivalent to:

UPDATE realdata SET data='nono' WHERE index=1;

which works as expected.

Can anyone enlighten me?

Thanks,
Markus

PS: My server version is PostgreSQL 7.4.5 on i386-pc-linux-gnu, compiled by GCC i386-linux-gcc (GCC) 3.3.4 (Debian 1:3.3.4-9)
--
markus schaber | dipl. informatiker
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