mysql - 依赖于多个表的可更新 View

Question

我正在阅读 MySQL 中的可更新 View :

To be more specific, a view is not updatable if it contains any of the following: ....

Certain joins (see additional join discussion later in this section)

然后:

It is sometimes possible for a multiple-table view to be updatable, assuming that it can be processed with the MERGE algorithm. For this to work, the view must use an inner join (not an outer join or a 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 的 View 。

依赖于可更新的多表 的 View 示例是什么？什么时候不呢？

Answer 1

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);

景色

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:您无法使用一条语句在两个基础表中插入或更新值

这个声明

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'