From Xojo Documentation
Attaches the SQLite database referred to by file to the database. It gives the newly attached database the name databaseName.
When a database has been attached, it is possible to do cross-database queries. In order to attach an encrypted database, you must pass the correct password for the database to be attached.
You should prefix all SQL queries to tables in the attached database with the databaseName.
This example attaches a database file to an existing, connected database, currentDB:
If currentDB.AttachDatabase(attachDBFile, "locations") Then // currentDB is already connected elsewhere
// Queries against the attached database would be prefixed with "locations", such as
// SELECT City FROM locations.Addresses WHERE ST = 'TX'