[Tarantool-discussions] Implicit cast for ASSIGNMENT

[Peter Gulutzan]

Hi,

Re this part of your proposal:
 >> 3) Values ​​of numeric types can be implicitly cast to other numeric
Earlier I replied:
 >I believe this but K. Yukhin decided to close issue#4216.

Update: K. Yukhin has re-opened
issue#4216 Silent NUMBER cast to INTEGER
https://github.com/tarantool/tarantool/issues/4216
and K. Osipov wrote:
 > OK, I didn't know it's ANSI. I withdraw my previous remarks and
 > side with Peter. Please do as he says about implicit casts of
 > numeric types.

Therefore I believe that everyone agrees with you,
"Values ​​of numeric types can be implicitly cast to other numeric"
for assignments.

Therefore ...

This will be true for anything that has a numeric data type,
now or in the planned future
(DECIMAL, DOUBLE, INTEGER, NUMBER, UNSIGNED).

Maybe this will be true for STRING.
UPDATE table_name SET integer_column = '1.1';
I said that is bad but I don't decide.

Maybe this will be true for SCALAR.
You announced that you will "fix" so values have type = SCALAR.
I do not know why, I do not know how, so I say "maybe".

You said there will be truncation not rounding. So:
CREATE TABLE t (s1 DOUBLE PRIMARY KEY, s2 INTEGER);
INSERT INTO t VALUES (1.9, NULL);
UPDATE t SET s2 = s1;
will cause no error and no warning, s2 will contain 1.

Documentation changes:

Fortunately in the compliance chart I wrote
https://www.tarantool.io/en/doc/2.4/book/sql/
that we support standard core feature E011-06
"Implicit casting among the numeric data types"
so that does not need to be changed.

Unfortunately in the SQL reference I wrote:
https://www.tarantool.io/en/doc/2.4/reference/reference_sql/sql/
"From number to INTEGER or UNSIGNED is allowed for
cast and assignment only if the result is not out of range,
and the number has no post-decimal digits."
so that does need to be changed.

Peter Gulutzan