keySet property
key_set identifies the rows to be yielded.
key_set names the primary keys of the rows in table to be yielded,
unless index is present. If index is present, then key_set instead names
index keys in index. It is not an error for the key_set to name rows
that do not exist in the database. Read yields nothing for nonexistent
rows.
Required.
Implementation
KeySet? keySet;