MySQL - employ created_date and updated_date?

In MySQL, is there an easy way for the following:

• On creation, both created_date and updated_date are set to the same TIMESTAMP
• On subsequent edits, updated_date is changed to the CURRENT_TIMESTAMP

Why is only one field allowed to use the CURRENT_TIMESTAMP as its default value? Why can't I have one default to the CURRENT_TIMESTAMP and the other use it only on update?

If I use now() for created_date and on update CURRENT_TIMESTA开发者_运维百科MP for updated_date, will they be the same on the creation of a row?

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That's just the way it is :)

But seriously, it's usually easier (less surprises) when you set those dates explicitly with 'now()' when you create/update the row.