DataSource.from_engine()

Query a caller’s database directly. Nothing is copied.

Usage

Source

DataSource.from_engine(
    engine,
    tables=None,
    exclude=None,
    dictionary=None,
)

A Snowflake or Databricks engine imports its catalog: the selection is resolved against the warehouse, access to it is verified for the current principal, and what it reports is folded into dictionary.

With tables unset on any other backend, its own listing is taken as given: it reports what exists, so there is nothing to check and no round trip worth paying for.

exclude takes unqualified object-name globs to drop from a warehouse catalog listing, such as "TMP_*". Only a warehouse has a listing to drop from, so any other engine refuses it.

On a warehouse dictionary is taken here because the catalog listing is folded into it during construction; on any other engine it is simply attached. Its governed definitions are lowered once the dialect and the final table set are known, at the end of construction.