CREATE TABLE orders(SER_NO NUMBER UNIQUE, ORDER_ID NUMBER, ORDER_DATE DATE NOT NULL, STATUS VARCHAR2(10) CHECK(status IN( ' CREDIT ' ,' CASH ')), PROD_ID NUMBER REFERENCES PRODUCTS(PRODUCT_ID), ORD_TOTAL NUMBER, PRIMARY KEY(order_id, order_date));
请问上述语句将自动为哪些列创建索引?
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