An abstract interface for representing federated data sources.

This interface abstracts away the specifics of working with various types of data sources.

Things one can do with a data source:

  • Determine the type of the data supplied by this data source by inspecting the federated_type property. The type returned should be a federated type. Note that depending on whether this data source contains one or a number of federated datasets, the type may or may not be a struct (with individual datasets appearing as elements of this struct).

  • Construct a new iterator for this data source by invoking iterator on it. Each iterator represents an independent pass over the data from this data source.

federated_type The type of the data returned by calling select on an iterator.



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Returns a new iterator for retrieving data from this data source.