Re: Updateable views

Greg Stark <gsstark@mit.edu> writes:
> I think you want to extend the SQL syntax to allow updating views, and
> implement plan nodes and executor functionality to handle them. So things
> like this works:

> UPDATE (SELECT id,val FROM t) SET val=0 where id < 100

> Then the rules you create on the views are just like the rules for SELECT,
> they simply mechanically replace the view with the view definition.

> I think this is the right approach because:

> a) I think creating the general rules to transform an update into an update on
>    the underlying table will be extremely complex, and you'll only ever be
>    able to handle the simplest cases. By handling the view at planning time
>    you'll be able to handle arbitrarily complex cases limited only by whether
>    you can come up with reasonable semantics.

Please provide an existence proof.  I don't really see any basis for the
claim that this will be simpler to implement --- the semantic problems
will be the same either way.
        regards, tom lane