[SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] underlined numbers in query diagrams unfiltered joins UNION ALL operation [See set operations] UNION operation [See set operations] unique indexes, performance effects of unique keys [See primary keys] updates in index, performance effects of uppercase text used in this book upstream nodes, when to choose USE_HASH hint USE_NL hint |