MySQL can be configured to have users who don't need to enter a password.
If you want to protect your data you should create a password for the root account, and create a new user for every set of accessrights you need, just like in oracle.
Rule nr1 in securing your server: Every account has a password
Rule nr2 Every user has his own account
Rule nr3 No accounts have rights to access data they don't need to access.