Tuning the Database Design Schema tuning Vertically partition relations to isolate the data that is accessed most often--only fetch needed information. 。 E.g.,split account into two,(account-number,branch-name)and (account-number,balance). Branch-name need not be fetched unless required Improve performance by storing a denormalized relation E.g.,store join of account and depositor;branch-name and balance information is repeated for each holder of an account,but join need not be computed repeatedly. Price paid:more space and more work for programmer to keep relation consistent on updates better to use materialized views (more on this later.. Cluster together on the same disk page records that would match in a frequently required join, compute join very efficiently when required. 11 Database System Concepts,5th Ed. 23.11 ©Silberschat乜，Korth and SudarshanDatabase System Concepts, 5 23.11 ©Silberschatz, Korth and Sudarshan th Ed. 11 Tuning the Database Design Schema tuning Vertically partition relations to isolate the data that is accessed most often -- only fetch needed information. • E.g., split account into two, (account-number, branch-name) and (account-number, balance). • Branch-name need not be fetched unless required Improve performance by storing a denormalized relation • E.g., store join of account and depositor; branch-name and balance information is repeated for each holder of an account, but join need not be computed repeatedly. • Price paid: more space and more work for programmer to keep relation consistent on updates • better to use materialized views (more on this later..) Cluster together on the same disk page records that would match in a frequently required join,  compute join very efficiently when required