View the Exhibit and examine the structure of ORD and ORD_ITEMS tables. The ORD_NO
column is PRIMARY KEY in the ORD table and the ORD_NO and ITEM_NO columns are
composite PRIMARY KEY in the ORD_ITEMS table. Which two CREATE INDEX
statements are valid? (Choose two.)
A.
CREATE INDEX ord_idx4 ON ord,ord_items(ord_no, ord_date,qty);
B.
CREATE INDEX ord_idx3 ON ord_items(item_no);
C.
CREATE INDEX ord_idx2 ON ord_items(ord_no);
D.
CREATE INDEX ord_idx1 ON ord(ord_no);
why not d
because with PK constraint index is already created