Re: [SQL] auto datetime update on UPDATE?

Tulassay Zsolt <zsolt(at)tek(dot)bke(dot)hu> writes:

> Hi,
>
> i have set up a table, where two fields (creation_dt and modification_dt)
> always get the actual date/time by default when doing an INSERT.
> my question is, how is it possible to let the field modification_dt
> change when doing an UPDATE?
> Is there a way to solve it in SQL?

To do this I use a trigger in plpgsql :

create function liens_maj_fun () returns opaque as '
begin
new.liens_maj := ''now'';
return new;
end;
' language 'plpgsql';

create trigger liens_maj_trig before update or insert
on liens for each row execute procedure liens_maj_fun();

Since it uses plpgsql don't forget to add it when you create your
base:

CREATE FUNCTION plpgsql_call_handler()
RETURNS opaque
AS '/usr/local/pgsql/lib/plpgsql.so'
LANGUAGE 'c';

CREATE TRUSTED PROCEDURAL LANGUAGE 'plpgsql'
HANDLER plpgsql_call_handler
LANCOMPILER 'PL/pgSQL';

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