Dmitry Dolgov <9erthalion6@gmail.com> writes:
> On Tue, Dec 22, 2020 at 12:19:26PM +0100, Pavel Stehule wrote:
>> I expect behave like
>>
>> update x set test[1] = 10; --> "[10]";
>> update x set test['1'] = 10; --> "{"1": 10}"
> Yes, I also was thinking about this because such behaviour is more
> natural.
I continue to feel that this is a fundamentally bad idea that will
lead to much more pain than benefit. People are going to want to
know why "test[1.0]" doesn't act like "test[1]". They are going
to complain because "test[$1]" acts so much differently depending
on whether they assigned a type to the $1 parameter or not. And
they are going to bitch because dumping and reloading a rule causes
it to do something different than it did before --- or at least we'd
be at horrid risk of that; only if we hide the injected cast-to-text
doesd the dumped rule look the way it needs to. Even then, the whole
thing is critically dependent on the fact that integer-type constants
are written and displayed differently from other constants, so it
won't scale to any other type that someone might want to treat specially.
So you're just leading datatype designers down a garden path that will be
a dead end for many of them.
IMO this isn't actually any saner than your previous iterations
on the idea.
I think so there can be some logic. But json has two kinds of very different objects - objects and arrays, and we should support both.
can be a good solution based on initial source value?
DECLARE v jsonb;
BEGIN
v := '[]';
v[1] := 10; v[2] := 20; -- v = "[10,20]"
v['a'] := 30; --> should to raise an error
v := '{}';
v[1] := 10; v[2] := 20; -- v = "{"1": 10, "2":20}"
v['a'] := 30; -- v = "{"1": 10, "2":20, "a": 30}"
When the source variable is null, then the default behavior can be the same like json objects. But it doesn't solve well numeric indexes.
because
v := '[]'
v[1.5] := 100; -- it is nonsense
but
v := '{}'
v[1.5] := 100; -- v = "{"1.5":100}" -- and this can have good benefit, but "1" and "1.0" are different keys.
But maybe we try to design some that are designed already. Is there some info about index specification in SQL/JSON?
Regards
Pavel
regards, tom lane