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).
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
...
Perhaps DEFINED is not the best keyword. Ultimately I want to know if a
variable has been assigned a value, as well as being able to mark a
variable as unassigned (though arguably you might not need to be able to
un-assign...).
--
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