你可能感興趣的試題

PO_DETAILS表包含以下列：
PO_NUM NUMBER NOT NULL, Primary Key
PO_LINE_ID NUMBER NOT NULL, Primary Key
PRODUCT_ID NUMBER Foreign Key to PRODUCT_ID column of the PRODUCTS table
QUANTITY NUMBER
UNIT_PRICE NUMBER(5,2)
請(qǐng)?jiān)u估以下語句：
ALTER TABLE po_details
DISABLE CONSTRAINT po_details_pk CASCADE;此語句用于完成什么任務(wù)（）

評(píng)估此CREATE TABLE語句的執(zhí)行結(jié)果：
CREATE TABLE part(
part_id NUMBER,
part_name VARCHAR2(25),
manufacturer_id NUMBER(9),
retail_price NUMBER(7,2) NOT NULL,
CONSTRAINT part_id_pk PRIMARY KEY(part_id),
CONSTRAINT cost_nn NOT NULL(cost),
CONSTRAINT FOREIGN KEY (manufacturer_id) REFERENCES manufacturer(id));
哪一行會(huì)導(dǎo)致產(chǎn)生錯(cuò)誤（）