Re: Trigger for updating view with join

Heh, it's me spamming you again :)

now -- asking for comments.

> > create trigger fsl_update instead of insert or update on fsl ...
> > 
> > but till now did not succeed in it.  Quick googlink did not help either.
> 
> Argh.  My google-fu is definitely low in the night ;)
> 
> for the record: it's right at 
> http://www.postgresql.org/docs/9.1/static/plpgsql-trigger.html 
> example 39-5

this example is only related, as the second one found at 
http://vibhork.blogspot.ru/2011/10/updateable-views-in-postgresql-91-using.html
(the latter does not allow inserting one-to many records)

after a bit if try'n'error, I'm with the following

--- 8< ---
create table machines (       mid     serial not null primary key,       mname   text not null unique
);

create table fs (       fsid    serial not null primary key,       mid     int not null references machines,
mpoint text not null
 
);
create unique index fs_mp on fs(mid, mpoint);

create view fsl as       select fsid, mid, mname, mpoint       from fs join machines using(mid);

create or replace function update_fsl() returns trigger as $$   declare       mmid    bigint;   begin       if (TG_OP =
'DELETE')then               -- only fs is deleted, not machine               delete from fs                   where
mpoint= OLD.mpoint and                       mid = (select mid from machines where mname=OLD.mname);               if
NOTFOUND then return NULL; else return OLD; end if;       elsif (TG_OP = 'INSERT') then               select mid into
mmidfrom machines where mname=NEW.mname;               if NOT FOUND then                   insert into machines (mname)
values(NEW.mname);                   select mid into mmid from machines where mname=NEW.mname;               end if;
          insert into fs (mid, mpoint) select mmid, NEW.mpoint;               return NEW;       elsif (TG_OP =
'UPDATE')then               -- only mpoint is allowed to be changed               update fs set mpoint = NEW.mpoint
             where mpoint = OLD.mpoint and                       mid = (select mid from machines where
mname=OLD.mname);              if NOT FOUND then return NULL; else return NEW; end if;       end if;   end;
 
$$ language plpgsql;
create trigger update_fsl instead of insert or update or delete on fsl for each row       execute procedure
update_fsl();
--- 8< ---

I looks all requested operations are fine, but I'm a bit reluctant: maybe I 
missed something easy but important?

Thanks!

-- 
Sincerely,
D.Marck                                     [DM5020, MCK-RIPE, DM3-RIPN]
[ FreeBSD committer:                                 marck@FreeBSD.org ]
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*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru ***
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