When you write your queries, you can include a database qualifier before the table names to allow you access to multiple databases.  So if you have two databases "Data1" and "Data2"  (BTW, these are the names defined in the database administrator), you can access either one by adding the qualifier before the table name

 

select * from "data1".code    --selects the inventory from the data1 database

 

select * from "data2".code    --selects the inventory from the data2 database