Hi Jan,
Welcome to the list (glad to hear the registration finally worked out).
A) Could be empty collection in a database created? This query db:add("MyDBName","","/NewCollectionName") perforemed in GUI creates collection NewCollectionName but copies there also bunch of other things used as example…
In BaseX, all collections are of implicit nature: A collection will automatically be created once you add a file as resource to the collection path or name. If you address a collection without contents, you will simply get no results:
* Create database with initial document: db:create('db', <x/>, 'collection1/input.xml')
* Return all documents in the specified collection: db:open('db', 'collection1')
B) Is it possible to grant various users different access rights to different collections under one database ? Eg. granting access rights to groups of users and/or creating roles ?
Access rights can only be granted to databases. However, databases are very light-weight in BaseX, so the usual modus operandi is to create multiple databases, which can all be addressed by a single XQuery expression.
See http://docs.basex.org/wiki/Databases for more information.
Hope this helps, Christian