消息推送系统

CREATE TABLE `users` (

`id` int(11) NOT NULL AUTO_INCREMENT,

`username` varchar(50) NOT NULL,

`password` varchar(255) NOT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `messages` (

`id` int(11) NOT NULL AUTO_INCREMENT,

`sender_id` int(11) NOT NULL,

`receiver_id` int(11) NOT NULL,

`content` text NOT NULL,

`send_time` datetime NOT NULL,

PRIMARY KEY (`id`),

走班排课软件

FOREIGN KEY (`sender_id`) REFERENCES `users`(`id`),

FOREIGN KEY (`receiver_id`) REFERENCES `users`(`id`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8;