Query available data sources deliberately ​

A SELECT can read tables, views, subqueries and documented table functions. On the server, a source named database.schema.table selects a registered managed database for that statement without changing the connection's selected database.

SELECT id, name
FROM reporting.main.products
WHERE id = 1;

This example requires a registered reporting database and its products table. It is a qualified server source, not a remote network address. The public interface does not promise federated execution against arbitrary external databases.

For an external dataset, import rows through a supported format or inspect a confined local file with file(). Define types explicitly and verify the imported data before joining it with application tables. The application owns any refresh procedure; a local copy does not stay synchronized by itself.

An embedded connection has its own documented namespace operations through ATTACH and DETACH. Keep those separate from the server's managed-database commands. In either mode, respect the rule against simultaneous access to one database file from separate processes.

See FROM sources, database selection, file input and deployment modes.