On Tue, Jan 10, 2017 at 1:03 AM, Jim Nasby <jim.na...@bluetreble.com> wrote:
> On 1/9/17 5:53 PM, Marko Tiikkaja wrote: > >> My idea was that the currently unsupported combination of NOT >> NULL and >> no DEFAULT would mean "has to be assigned to a non-NULL value >> before it >> can be read from, or an exception is thrown". Solves the most >> common >> use case and is backwards compatible. >> >> >> That won't allow you to use a variable in multiple places though... >> is there a reason we couldn't support something like IS DEFINED and >> UNSET? >> >> >> I don't understand what your use case is. Could you demonstrate that >> with some code you'd write if these features were in? >> > > One use case is NEW and OLD in triggers. Checking to see if one or the > other is set is easier than checking TG_OP. It's also going to be faster > (probably MUCH faster; IIRC the comparison currently happens via SPI). > This sounds useless. > Another case is selecting into a record: > > EXECUTE ... INTO rec; > IF rec IS DEFINED THEN > ELSE > EXECUTE <something else> INTO rec; > IF rec IS DEFINED THEN > And this a workaround for non-functional FOUND. I can't get excited about this idea based on these examples. .m
