his module contains a function to return an iterator (see the Iterator
module) that returns the rows of a database query, one at a time.

This is marginally more useful than simply calling prepare and execute,
and then repeatedly calling fetchrow_hashref; since this one function
bundles up the calls to all three of those DBI methods.

But the real usefulness of this interface is that it can be chained
together with other Iterator functions. The "idb_rows" iterator has the
same interface as any other interface, making it interchangeable with
iterators of any other source (for example, files), and usable with the
iterator manipulation functions in the Iterator::Util module.
