Is it OK to have database name the same as user name in MySQL?

Yes, that is absolutely fine and quite a common practice. They are mutually exclusive in use and will not cause any problems.

All you need to ensure is that they comply with username and schema naming conventions:

  • http://dev.mysql.com/doc/refman/5.6/en/user-names.html
  • http://dev.mysql.com/doc/refman/5.6/en/identifiers.html

It is ok to name the user and the DB the same, you should not have problem.

But from a security point of view you should maybe use another username.