创建表时将auto_increment设置为30的目的是什么?

问题描述

CREATE TABLE IF NOT EXISTS `qdz76_piteachers` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `teacher_name` varchar(250) NOT NULL,
  `teacher_alias` varchar(250) NOT NULL,
  `teacher_role` varchar(50) NOT NULL,
  `image_folderlrg` int(11) NOT NULL,
  `teacher_image_lrg` varchar(250) NOT NULL,
  `teacher_email` varchar(100) NOT NULL,
  `teacher_website` varchar(250) NOT NULL,
  `teacher_description` text NOT NULL,
  `published` tinyint(3) NOT NULL,
  `ordering` int(11) NOT NULL,
  `teacher_view` tinyint(3) NOT NULL,
  `checked_out` tinyint(1) NOT NULL DEFAULT '0',
  `checked_out_time` datetime DEFAULT NULL,
  `user` int(11) NOT NULL,
  `language` char(7) NOT NULL DEFAULT '*',
  `featured` tinyint(3) NOT NULL DEFAULT '0',
  `metakey` text NOT NULL,
  `metadesc` text NOT NULL,
  `lastname` varchar(250) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=30 ;

我对mysql很陌生，并且已阅读此页面 http ://dev.mysql.com/doc/refman/5.5/en/create-table.html ，看起来AUTO_INCREMENT = 30在table_option部分中，但我仍然不明白这里是指.这是否意味着所有int字段的auto_increment均为30?

I am very new to mysql and have read this page http://dev.mysql.com/doc/refman/5.5/en/create-table.html, it looks like AUTO_INCREMENT = 30 is in table_option section, but I still don't understand what AUTO_INCREMENT = 30 here means. Does it mean all int fields have auto_increment as 30?

推荐答案

实际上，每当您从服务器准备转储或从phpmyadmin获取表结构时，它都会根据现有表值为您提供auto_increment值，因此您将获得它作为30.

Actually whenever you prepare a dump from server or get table structure from phpmyadmin then it provide you auto_increment value as per existing table values, so you will be getting it as 30.

无论何时创建新表，都无需提及auto_increment(如果没有特定原因)，因为它会自动从1开始.

Whenever you create new table, then no need to mention auto_increment (if there is no specific reason) as it automatically start from 1.

出于某些特定原因，您需要告诉mysql我的auto_increment值应从该数字开始，在这种情况下，您需要在表创建语法中指定它.

In some specific reason you need to tell mysql that my auto_increment value should start from this number in this case you need to specify it in your table creation syntax.

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