another load data infile issue

MariaDB allows NULLs in a FK field, but 'load data infile' insists on 
NOT NULL

load data infile:
"ERROR 1452 (23000): Cannot add or update a child row: a foreign key 
constraint fails (`db`.`table`, CONSTRAINT `ibfk_1` FOREIGN KEY 
(`fkcol`) REFERENCES `parenttable` (`parentcolumn`))


MariaDB [db]> insert into tbl values (999999,'test',null);
Query OK, 1 row affected (0.161 sec)

(the third column is the FK column)