Обсуждение: IF ROW( NEW ) <> ROW( OLD )
Is it possible to "cast" a table type to a ROW so that Row-Wise comparison can be achieved? -- Regards, Richard Broersma Jr. Visit the Los Angles PostgreSQL Users Group (LAPUG) http://pugs.postgresql.org/lapug
On Wed, Jun 25, 2008 at 4:40 PM, Joshua D. Drake <jd@commandprompt.com> wrote: > I have never tried it but you may be able to do it with a composite > type. True. However, I was under the impression that table types were essentially composite types. So I thought that composite types would behave the same. I could manually expand the composite type OLD and NEW to enumerate each field and make a row wise comparison. However, I was hoping to avoid that. -- Regards, Richard Broersma Jr. Visit the Los Angles PostgreSQL Users Group (LAPUG) http://pugs.postgresql.org/lapug
"Richard Broersma" <richard.broersma@gmail.com> writes:
> I could manually expand the composite type OLD and NEW to enumerate
> each field and make a row wise comparison. However, I was hoping to
> avoid that.
I think IF ROW(NEW.*) <> ROW(OLD.*) will work in recent releases.
Actually you'd better use IF ROW(NEW.*) IS DISTINCT FROM ROW(OLD.*) ...
you really don't want to rely on <> as it will not give the behavior
you want in the presence of null columns.
regards, tom lane
On Wed, Jun 25, 2008 at 8:17 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > I think IF ROW(NEW.*) <> ROW(OLD.*) will work in recent releases. > > Actually you'd better use IF ROW(NEW.*) IS DISTINCT FROM ROW(OLD.*) ... > you really don't want to rely on <> as it will not give the behavior > you want in the presence of null columns. Thanks that worked! -- Regards, Richard Broersma Jr. Visit the Los Angles PostgreSQL Users Group (LAPUG) http://pugs.postgresql.org/lapug