Which statement is true?
A.
Stored functions can be called from the SELECT and WHERE clauses only.
B.
Stored functions do not permit calculations that involve database links in a distributed
environment.
C.
Stored functions cannot manipulate new types of data, such as longitude and latitude.
D.
Stored functions can increase the efficiency of queries by performing functions in the query
rather than in the application.
Explanation:
User-defined functions increase the efficiency of queries by applying the functions in the query
itself. This drastically improves the performance because the query is designed to use the
function instead of using the query and functions separately from client-side tools when enforcing
application logic.
Incorrect Answers:
A: Functions can be invoked as part of SELECT statements (in the column list, WHERE, GROUP
BY, HAVINGand ORDER BY clauses), in the UPDATE statement (in the SET and WHERE
clause), in the DELETEstatement (in the WHERE clause), and in the INSERT statement (in the
VALUES clause).
B: Functions allow calculations on data across a database link.C. Functions can be used to
manipulate these data types.