The main problem is that you might have trouble moving data to PostgreSQL. Just imagine you want to move some data and there is a NOT NULL constraint on the PostgreSQL side. We know MySQL does not care:
MariaDB [test]> SELECT CAST('2014-02-99 10:00:00' AS datetime) AS x, CAST('2014-02-09 10:00:00' AS datetime) AS y; +------+---------------------+ | x | y | +------+---------------------+ | NULL | 2014-02-09 10:00:00 | +------+---------------------+ 1 row in set, 1 warning (0.00 sec)
PostgreSQL will definitely reject February 99 (for a good reason), but it might not accept the NULL value either if you have explicitly banned it (for a good reason). What you have to do in this case is to somehow fix the data to make sure ...