There are several ways to manage user connections.
You can:
- Limit the number of active logins for a single user – assign user to a
                    login policy in which the MAX_CONNECTIONS login policy option is set.
 
- Lock a user account:
- Explicitly – assign user to a login policy in which the LOCKED
                            option is set to ON.
 
- Implicitly – assign user to a login policy in which the
                            MAX_FAILED_LOGIN_ATTEMPTS option is set. If the user exceeds the value
                            when attempting to log in, his or her user account is locked.
 
 
- Set a password expiry condition – assign user to a login policy in which
                    the PASSWORD_EXPIRY_ON_NEXT_LOGIN login policy option is set. You can also
                    execute the CREATE USER or ALTER USER
                    statements, including the FORCE PASSWORD CHANGE clause.
 
Assigning a login policy to a user, or forcing a password change requires the
            MANAGE ANY USER system privilege. Creating or altering a login policy requires the
            MANAGE ANY LOGIN POLICY system privilege.