UDT_CATALOG view, 515
UDT_NAME view, 515
UDT_SCHEMA view, 515
UML (Unified Modeling Language), 33, 398
UNDER (reserved word), 466
UNICODE() function, 184, 479
UNION command, 453
union queries
federating data, 249–250
overview, 247–249
partitioning data, 249–251
performance and, 250–251
scaling considerations, 250–251
UNION (reserved word), 461, 463
unique constraint, 333
unique identifiers, 30
UNIQUE (reserved word), 461, 463
UNIQUE_CONSTRAINT_CATALOG view, 513
UNIQUE_CONSTRAINT_NAME view, 513
UNIQUE_CONSTRAINT_SCHEMA view, 513
UniqueIdentifier type, 330–331
UNKNOWN (reserved word), 463, 466
UNNEST (reserved word), 466
unshipped product orders and subqueries, 294
UPDATE command, 455
update locks, 17
Update procedure, 373–374
UPDATE (reserved word), 461, 463
UPDATE statement, 264–269
UPDATE_RULE view, 514
UPDATETEXT (reserved word), 461
UPPER() function, 188–190, 479
UPPER (reserved word), 464
USAGE (reserved word), 464, 466
USE (reserved word), 461
user interface, 402–403
USER (reserved word), 461, 464
user-defined aggregate function, 212
user-defined function, creation of, 119–120
user-defined functions
inline table-valued functions, 390–391
multi-statement table-valued functions, 391–393
overview, 386
scalar functions, 386–390
USER_ID() function, 478
USER_id() function, 200
USER_NAME() function, 200, 202, 482
USER_NAME option, 344
users accessing data, number of, 399
USING (reserved word), 464, 466