我Updateable View
在MySQL中阅读:
更具体地说,如果视图包含以下任何内容,则它是不可更新的: ....
某些联接(请参阅本节后面的附加联接讨论)
在那之后:
假设可以使用 MERGE 算法对其进行处理,多表视图有时可能是可更新的。为此,视图必须使用内部联接(不是外部联接或 UNION)。
但是没有明确的例子,我没有成功更新我创建的涉及NATURAL JOIN
.
multi-tables
依赖于可更新的视图的示例是什么?什么时候不?
示例表架构
CREATE TABLE customers(customer_id INT, `name` VARCHAR(32));
CREATE TABLE orders(order_id INT, customer_id INT, order_date DATE);
风景
CREATE VIEW vw_orders AS
SELECT order_id, o.customer_id order_customer_id, c.customer_id, c.name customer_name, order_date
FROM orders o INNER JOIN
customers c ON o.customer_id = c.customer_id;
然后你可以像这样插入
INSERT INTO vw_orders (customer_id, customer_name) VALUES (1, 'Customer1');
INSERT INTO vw_orders (order_id, order_customer_id, order_date) VALUES (1, 1, CURDATE());
或更新
UPDATE vw_orders SET customer_name = 'Customer11' WHERE customer_id = 1;
注意:您将无法使用单个语句在两个基础表中插入或更新值
这个说法
INSERT INTO vw_orders (customer_id, customer_name, order_id, order_customer_id, order_date)
VALUES (2, 'Customer2', 2, 2, CURDATE());
将因错误而失败
Can not modify more than one base table through a join view 'vw_orders'