Get Database from String

Hello ARIS Community, 

i have a question concerning local services in the APG. Can someone tell me how i can get the database object based on the database name?

I have defined the databaseName and the modelGuid as inputs so i can get them like this: 

var guids = input.guids; 

var databaseName = input.database; 

Now my question is: How can i get the real database object, so i can search for the model GUID? Apparently the global objects (ArisData, Context, etc.) are not working in local services.

Thanks in advance! 

Regards, 

Richard