foreign_key.txt

来自「orale培训教材包括了所有的sql说明和实例」· 文本 代码 · 共 36 行

ALTER TABLE plsql101_purchase
ADD CONSTRAINT plsql101_purchase_fk_product
          FOREIGN KEY (product_name) 
          REFERENCES plsql101_product;

-- 练习: Fixing child values & creating the FK constraint
UPDATE plsql101_purchase
SET    product_name = 'Round Chrome Snaphoo'
WHERE  product_name = 'Round Snaphoo';

ALTER TABLE plsql101_purchase
ADD CONSTRAINT plsql101_purchase_fk_product
          FOREIGN KEY (product_name) 
          REFERENCES plsql101_product;


-- 练习: Attempting to enter a child record without a matching 
-- parent record
INSERT INTO plsql101_purchase VALUES (
     'Small Widgee', 'CA', '17-7月-03', 1)
;

-- Corrected version
INSERT INTO plsql101_purchase VALUES (
     'Small Widget', 'CA', '17-7月-03', 1)
;



-- 为plsql101_purchase建立FOREIGN KEY ,通过salesperson字段
--与plsql101_person建立关联
ALTER TABLE plsql101_purchase
ADD CONSTRAINT plsql101_purchase_fk_person
          FOREIGN KEY (salesperson)
          REFERENCES plsql101_person;