ctime 为创建时间, mtime 是修改时间默认CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP

CREATE TABLE `trades_platform` (
	`id` INT(10) UNSIGNED NULL DEFAULT NULL,
	`type` ENUM('A','B','C') NOT NULL,
	`login` VARCHAR(10) NOT NULL,
	`password` VARCHAR(10) NOT NULL,
	`ctime` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
	`mtime` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
)
COMMENT='平台'
ENGINE=InnoDB;
		

我们还可以让mtime默认为NULL,这样更节省存储空间。

	`ctime` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
	`mtime` TIMESTAMP NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,