Prior to Version 7.0
there wasn't an equivalent to USE
. You had to log in to specific databases on the server however you can still access any object using. database.schema.objectname
Post Version 7.0
the equivalent is Set Catalog
SET CATALOG <database_name>
Regarding your specific inquiry. Please consider using _V_TABLE_XDB
instead of _V_TABLE
. This system table should provide you with a list of all tables, not just those in the database you are connected to.