字符集
表格创建规范
`update_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE在更新时 CURRENT_TIMESTAMP COMMENT '更新时间',
3.例子
CREATE TABLE `t_friend_chat` (
`id` bigint unsigned NOT NULL COMMENT '主键id',
`from_user_id` bigint unsigned NOT NULL DEFAULT '0' COMMENT '消息发送者',
`to_user_id` bigint unsigned NOT NULL DEFAULT '0' COMMENT '消息接收者',
`content` text CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT '消息内容',
`content_type` int unsigned NOT NULL DEFAULT '0' COMMENT '消息类型',
`server_from_recall` int unsigned NOT NULL DEFAULT '0' COMMENT '服务器有没有给发送者回调',
`server_to_send` int unsigned NOT NULL DEFAULT '0' COMMENT '服务器有没有给接受者发送消息',
`server_to_recall` int unsigned NOT NULL DEFAULT '0' COMMENT '服务器有没有收到接受者的回调',
`status` int unsigned NOT NULL DEFAULT '0' COMMENT '状态(0,未完成,1,已完成,2,撤回)',
`finish_time` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL DEFAULT '' COMMENT '消息发送成功时间',
`withdraw_time` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL DEFAULT '' COMMENT '消息撤回时间',
`revision` int unsigned NOT NULL DEFAULT '0' COMMENT '乐观锁',
`creator` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL DEFAULT '' COMMENT '创建人',
`create_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
`updater` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL DEFAULT '' COMMENT '更新人',
`update_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',
`del_flag` int unsigned NOT NULL DEFAULT '0' COMMENT '删除标志(0,未删除,1删除)',
PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci ROW_FORMAT=DYNAMIC COMMENT='好友聊天';