# User authorization exceptions

SQL exceptions are returned when errors occur with user authorizations.

Derby validates the database properties when you set the properties. An exception is returned if you specify an invalid value when you set these properties.

If a user attempts to connect to a database but is not authorized to connect to that database, the SQLException 04501 is returned.

If a user with read-only access attempts to write to a database, the SQLException 08004 `- connection refused` is returned.

Parent topic: Setting access for individual users
Related reference
Read-only and full access permissions