activerecord update_attributes have a strange action with date

rubyonrails-talk
1

I am using activerecord 2.1.0 and mysql,and with mysql 2.7 driver. I have seen that when I use update_attributes,the date value have a strange action.

Think we have a table Tests with id int, dt datetime

and when I use, a[:dt] = "20081128" test = Test.new test.update_attributes(a)

it ran ok,

but when I set the date value to "31000101" the dt had been set to NULL.

anyone have same problem?