Response: That why I asked you how should I need to do when I use more than one database on a context.
With XQuery, you can open and process as many databases as you want; see e.g:
for $c in 1 to 100 let $dbname := "db" || $c return db:open($dbname)
There will be no need at all to explicitly bind databases to a context.
Hope this helps, Christian