MySQL 笔记（五）MySQL 角色 & SQL CHECK 约束 MySQL关于check约束无效的解决办法

MySQL ROLE

MySQL 8.0 Reference Manual  /  Security  /  MySQL User Account Management  /  Using Roles

how to create role on MySQL database

mysql 8.0 才支持角色。

创建新角色：

CREATE ROLE 'app_developer', 'app_read', 'app_write';

将权限赋予角色：

GRANT ALL ON app_db.* TO 'app_developer';
GRANT SELECT ON app_db.* TO 'app_read';
GRANT INSERT, UPDATE, DELETE ON app_db.* TO 'app_write';

创建新用户：

CREATE USER 'dev1'@'localhost' IDENTIFIED BY 'dev1pass';
CREATE USER 'read_user1'@'localhost' IDENTIFIED BY 'read_user1pass';
CREATE USER 'read_user2'@'localhost' IDENTIFIED BY 'read_user2pass';
CREATE USER 'rw_user1'@'localhost' IDENTIFIED BY 'rw_user1pass';

将角色赋予用户：

GRANT 'app_developer' TO 'dev1'@'localhost';
GRANT 'app_read' TO 'read_user1'@'localhost', 'read_user2'@'localhost';
GRANT 'app_read', 'app_write' TO 'rw_user1'@'localhost';

SQL CHECK 约束

http://www.w3school.com.cn/sql/sql_check.asp

MySQL关于check约束无效的解决办法

没找到官方文档。查了下资料发现 MySQL 不支持 CHECK ，加不加都一样。。

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示例：

DROP TABLE IF EXISTS employee;
CREATE TABLE employee (
    name VARCHAR(50) NOT NULL,
    phone_num VARCHAR(20) NOT NULL,
    id CHAR(8),
    sex CHAR(1),
    
    PRIMARY KEY(id),
    
    CONSTRAINT check_sex CHECK (sex IN ('f', 'm')),
    CONSTRAINT check_id CHECK (id LIKE 'E_______')
    
)    ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO employee
    (name, 
    phone_num, 
    id, 
    sex)
VALUES
    ('李四',
    '15159000122',
    'E2008001',
    'f');
    
DROP TABLE IF EXISTS product;
CREATE TABLE product (
    name VARCHAR(50) NOT NULL,
    id CHAR(9),
    product_type VARCHAR(50) NOT NULL,
    production_date DATE,
    
    PRIMARY KEY(id),
    
    CONSTRAINT check_id CHECK (id LIKE 'P%'
    AND SUBSTRING(id, 2, 4) = YEAR(production_date))
    
)    ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO product
    (name, 
    id, 
    product_type, 
    production_date)
VALUES
    ('飞碟迷宫',
    'P20080021',
    '玩具',
    '2008-10-22');

CREATE TABLE customer (
    name VARCHAR(50) NOT NULL,
    id CHAR(9),
    sex CHAR(1) NOT NULL,
    department VARCHAR(50) NOT NULL,
    salary VARCHAR(50) NOT NULL,
    job_title VARCHAR(50) NOT NULL,
    
    PRIMARY KEY(id),
    
    CONSTRAINT check_id CHECK (id LIKE 'C%')
    
)    ENGINE=INNODB DEFAULT CHARSET=utf8;    

CREATE TABLE order_master (
    id CHAR(12) PRIMARY KEY,
    customer_id CHAR(9) NOT NULL,
    employee_id CHAR(8) NOT NULL,
    total DECIMAL(8, 2) DEFAULT 0,
    -- order_date DATE DEFAULT CURDATE(), 这两行是错的，MySQL目前字段的默认值不支持函数
    -- shipping_date DATE DEFAULT CURDATE(), 另外一种解决方案是由应用程序插入默认值
    order_date TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    -- shipping_date TIMESTAMP DEFAULT CURRENT_TIMESTAMP, there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE clause
    -- 或者是用触发器来做
    invoice_number VARCHAR(50) UNIQUE,
    
    FOREIGN KEY (customer_id) 
        REFERENCES customer(id),
    
    FOREIGN KEY (employee_id) 
        REFERENCES employee(id)        
)    ENGINE=INNODB DEFAULT CHARSET=utf8;    

CREATE TABLE order_detail (
    order_id CHAR(12) NOT NULL,
    product_id CHAR(9) NOT NULL,
    quantity INT NOT NULL,
    price DECIMAL(8, 2),
    
    FOREIGN KEY (order_id) 
        REFERENCES order_master(id),
    
    FOREIGN KEY (product_id) 
        REFERENCES product(id)    
)    ENGINE=INNODB DEFAULT CHARSET=utf8;