Hi All,

I recently had a need to have conditional update rules on a view. This
didn't work too well:

CREATE RULE insert_one AS
ON INSERT TO one WHERE NEW.id IS NULL
DO INSTEAD (
INSERT INTO _simple (id, guid, state, name, description)
VALUES (NEXTVAL('seq_kinetic'), NEW.guid, NEW.state, NEW.name,
NEW.description);

INSERT INTO simple_one (id, bool)
VALUES (CURRVAL('seq_kinetic'), NEW.bool);
);

CREATE RULE promote_one AS
ON INSERT TO one WHERE NEW.id IS NOT NULL
DO INSTEAD (
UPDATE _simple
SET guid = NEW.guid, state = NEW.state, name = NEW.name,
description = NEW.description
WHERE id = NEW.id;

INSERT INTO simple_one (id, bool)
VALUES (NEW.ID, NEW.bool);
);

I found this in the docs to explain the issue:

> There is a catch if you try to use conditional rules for view updates:
> there must be an unconditional INSTEAD rule for each action you wish
> to allow on the view.

Well, I didn't have an unconditional update rule, so I added one
without removing the other two:

CREATE RULE nothing_one AS
ON INSERT TO one DO INSTEAD NOTHING;

And it worked! Now I can have an insert do an INSERT or UPDATE on
another table magically.

But my question is this: Is this a known and supported behavior? If
not, is it likely to change? If so, how is the order or rules evaluated
when a query is sent to the database? Order of definition?
Alphabetically?

TIA,

David

PS: Please Cc me in replies as I am not subscribed to the list. Thanks!


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