Hi, Federico!
On Sep 02, Federico Razzoli wrote:
> Ciao,
>
> I wanted to add some info in the CREATE PROCEDURE page in the KB, but
> I think that some info about CREATE PROCEDURE clauses miss both in the
> kb and in the MySQL manual.
>
> * [NOT] DETERMINISTIC. From MySQL docs:
> "A routine is considered “deterministic” if it always produces the
> same result for the same input parameters, and “not deterministic”
> otherwise."
> What does this exactly mean for procedures? OUT and INOUT parameters?
> Resultsets returned by the procedure? Both?
It doesn't really matter.
For stored functions, optimizer uses the value of [NOT] DETERMINISTIC to
optimize function calls.
But for procedures it's not used for anything, as far as I know.
> * NO SQL: As far as I understand, even SET is a SQL statement. I guess
> that a "no sql" function is something like
> CREATE FUNCTION x(n INT) RETURNS INT
> BEGIN
> RETURN n*2;
> END;
Not quite.
As far as I understand,
"NO SQL" means that there's no SQL in the routine *at all*.
Like,it might be written on C or ADA or whatever sql standard specifies:
<language clause> ::= LANGUAGE <language name>
<language name> ::=
ADA
| C
| COBOL
| FORTRAN
| M | MUMPS
| PASCAL
| PLI
| SQL
It's particularly important if a routine has the EXTERNAL clause,
instead of the BEGIN ... END body.
But MariaDB does not support EXTERNAL or any other LANGUAGE besides SQL.
> I'm sorry if this info is already written somewhere, but I really
> wasn't able to find it - and I feel that the KB should specify things
> like these.
It's only on the SQL-99 Complete, Really pages:
https://mariadb.com/kb/en/create-procedurefunctionmethod-statement/#language-subclause
https://mariadb.com/kb/en/create-procedurefunctionmethod-statement/#sql-data-access-indication-subclause
Regards,
Sergei
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