* Cheng Wang via dev [22/08/09 09:43]:
> I am working on improving the schema disagreement issue. I need some dtests
> which can reproduce the schema disagreement. Anyone know if there are any
> existing tests for that? Or something similar?
cassandra-10250 is a good start.
--
K
variable with NULLs or a static cells,
and leave you wondering what to do next. FETCH will RAISE NOT
FOUND condition, a kind of exception you can handle separately.
Totally different in Cassandra where NULL is a deletion marker and
NULLs are indistinguishable from missing values.
--
Konstantin Osipov, Moscow, Russia
andra results, there is no way to distinguish null values
from absence of a row. Branching, thus, without being able to
branch based on the absence of a row, whatever specific syntax
is used for such branching, is incomplete.
More broadly, SQL/PSM has exception and condition statements, not
ju
atic rows, different from LWT
and SELECTs.
This is why I was making all these comments about missing rows
-there is no incongruence in classic SQL, any vendor, because a)
there are no static rows b) NULLs are first-class values,
distinguishable from unset values.
--
Konstantin Osipov, Moscow, Russia
T return the static row if there is no match for the
clustering key, or return NULL row?
I am asking because SELECT currently does not return any rows if
there is no clustering key matching the WHERE clause, but a conditional UPDATE
chooses the static row to check conditions instead, if it's present.
--
Konstantin Osipov, Moscow, Russia
ld handle
NOT FOUND condition. In SQL, that would trigger activation of a
CONTINUE handler.
It's hard to see how one can truly branch the logic without it.
Relying on NULL content of a cell would be full of gotchas.
--
Konstantin Osipov, Moscow, Russia
