Relation Instance The current values (relation instance)of a relation are specified by a table An element t of r is a tuple,represented by a row in a table attributes (or columns) customer name customer street customer_city Jones Main Harrison Smith North Rye tuples Curry North Rye (or rows) Lindsay Park Pittsfield customer Database System Concepts-5th Edition,Oct 5,2006 27 ©Silberschat乜，Korth and SudarshanDatabase System Concepts - 5 2.7 ©Silberschatz, Korth and Sudarshan th Edition, Oct 5, 2006 Relation Instance The current values (relation instance) of a relation are specified by a table An element t of r is a tuple, represented by a row in a table Jones Smith Curry Lindsay customer_name Main North North Park customer_street Harrison Rye Rye Pittsfield customer_city customer attributes (or columns) tuples (or rows)