請(qǐng)觀(guān)察PRODUCT表和SUPPLIER表的結(jié)構(gòu):
PRODUCT
PRODUCT_ID NUMBER NOT NULL, Primary Key
PRODUCT_NAME VARCHAR2 (25)
SUPPLIER_ID NUMBER ( SUPPLIER表的SUPPLIER_ID的外鍵)
LIST_PRICE NUMBER (7,2)
COST NUMBER (7,2)
QTY_IN_STOCK NUMBER
QTY_ON_ORDER NUMBER
REORDER_LEVEL NUMBER
REORDER_QTY NUMBER
SUPPLIER
SUPPLIER_ID NUMBER NOT NULL, Primary Key
SUPPLIER_NAME VARCHAR2 (25)
ADDRESS VARCHAR2 (30)
CITY VARCHAR2 (25)
REGION VARCHAR2 (10)
POSTAL_CODE VARCHAR2 (11)
請(qǐng)?jiān)u估以下語(yǔ)句:
ALTER TABLE suppliers
DISABLE CONSTRAINT supplier_id_pk CASCADE;
該語(yǔ)句用于執(zhí)行什么任務(wù)()
A.刪除引用SUPPLIERS表的所有約束條件
B.刪除對(duì)FOREIGNKEY表的FOREIGNKEY約束條件
C.刪除引用PRODUCTS表的所有約束條件
D.禁用所有依賴(lài)于PRODUCTS表的SUPPLIER_ID列的完整性約束條件
E.禁用所有依賴(lài)于SUPPLIERS表的SUPPLIER_ID列的完整性約束條件