Connecting to another mysql database and update database tables when other database is update

Is it possible to connecting a remote mysql server and auto update another database in the same time? For example my database:

Database one: user id  user name  pass

When adding or updating user in database two, user name in database one updates. How can I do this if possib开发者_如何学Pythonle? Thanks in advance

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Automating this inside mySQL may be possible using triggers but that is complex and requires mySQL 5.

Wouldn't it be an option to do the logic in PHP? Adding a query to update database B whenever database A is updated?