mysql水平分表和垂直分表

在网上找了很多mysql分表的做法，都大同小异，天下文章一大抄，哈哈，今天我也来抄一抄，不过我是经过实战操作的。

参考的是这里 https://www.cnblogs.com/lucky-man/p/6207873.html。我的做法是：

水平分表

1，假设现在是存储用户聊天记录(哈哈，还是抄的上面链接同志的) 预先建了3个表然后根据用户uid取模来判定将聊天记录存放在哪个表中：

CREATE TABLE `msg_0` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `uid` int(11) NOT NULL,
  `content` varchar(50) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8

CREATE TABLE `msg_1` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `uid` int(11) NOT NULL,
  `content` varchar(50) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8

CREATE TABLE `msg_2` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `uid` int(11) NOT NULL,
  `content` varchar(50) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8

2，php 代码

<?php
header("Content-type=text/html;charset=utf8");
$link = mysql_connect("localhost",'root','111111');
if (!$link){
    die("数据库连接失败");
}
mysql_select_db("test");
//水平分表
$uid = mt_rand(1,100);//模拟用户uid
$yu = $uid%3; //分了3个表 所以是%3来取模

$table = "msg_".$yu; //判断是哪个表
$content = "hello word_".$table;

//插入数据
$sql="insert into ".$table."(uid,content) values(".$uid.",'".$content."')";
$re = mysql_query($sql);


//查询数据
$s = "select * from ".$table;
$re = mysql_query($s);
 while ($row = mysql_fetch_array($re,MYSQL_ASSOC )){
     ps($row);
 }


function ps($str){
    echo "<pre>";
    print_r($str);
}

function pse($str){
    echo "<pre>";
    print_r($str);
    exit;
}
?>

就是上面那么多内容，水平分表真的就这么简单么？额，反正在网上找的差不多讲的都是这个意思。还有一种是利用mysql自身的merge引擎分表，跟我这个差不多，自己查查吧！

垂直分表

垂直分表就是将一个表中不经常用到的，或者像text这种类型比较大的字段挪到一个表中，其他常用的字段单独一个表，

如：现在有个user表：如下，有很多字段，现在分成两个表，一个user1用了存放用户主要的属性字段，另一个表user2，用了存放各种时间相关的字段

mysql> desc user;
+----------------+---------------------+------+-----+---------+----------------+
| Field          | Type                | Null | Key | Default | Extra          |
+----------------+---------------------+------+-----+---------+----------------+
| id             | int(10) unsigned    | NO   | PRI | NULL    | auto_increment |
| group_id       | int(10) unsigned    | NO   |     | 0       |                |
| username       | varchar(32)         | NO   | MUL |         |                |
| nickname       | varchar(50)         | NO   | MUL |         |                |
| password       | varchar(32)         | NO   |     |         |                |
| salt           | varchar(30)         | NO   |     |         |                |
| email          | varchar(100)        | NO   | MUL |         |                |
| mobile         | varchar(11)         | NO   | MUL |         |                |
| avatar         | varchar(255)        | NO   |     |         |                |
| birthday       | date                | NO   |     | NULL    |                |
| prevtime       | int(10) unsigned    | NO   |     | 0       |                |
| logintime      | int(10) unsigned    | NO   |     | 0       |                |
| loginip        | varchar(50)         | NO   |     |         |                |
| loginfailure   | tinyint(1) unsigned | NO   |     | 0       |                |
| joinip         | varchar(50)         | NO   |     |         |                |
| jointime       | int(10) unsigned    | NO   |     | 0       |                |
| createtime     | int(10) unsigned    | NO   |     | 0       |                |
| updatetime     | int(10) unsigned    | NO   |     | 0       |                |

mysql> desc user1;
+----------------+---------------------+------+-----+---------+----------------+
| Field          | Type                | Null | Key | Default | Extra          |
+----------------+---------------------+------+-----+---------+----------------+
| id             | int(10) unsigned    | NO   | PRI | NULL    | auto_increment |
| group_id       | int(10) unsigned    | NO   |     | 0       |                |
| username       | varchar(32)         | NO   | MUL |         |                |
| nickname       | varchar(50)         | NO   | MUL |         |                |
| password       | varchar(32)         | NO   |     |         |                |
| salt           | varchar(30)         | NO   |     |         |                |
| email          | varchar(100)        | NO   | MUL |         |                |
| mobile         | varchar(11)         | NO   | MUL |         |                |
| avatar         | varchar(255)        | NO   |     |         |                |
| birthday       | date                | NO   |     | NULL    |                |

mysql> desc user2;
+----------------+---------------------+------+-----+---------+----------------+
| Field          | Type                | Null | Key | Default | Extra          |
+----------------+---------------------+------+-----+---------+----------------+
| uid             | int(10) unsigned    | NO  |     |         |
| prevtime       | int(10) unsigned    | NO   |     | 0       |                |
| logintime      | int(10) unsigned    | NO   |     | 0       |                |
| loginip        | varchar(50)         | NO   |     |         |                |
| loginfailure   | tinyint(1) unsigned | NO   |     | 0       |                |
| joinip         | varchar(50)         | NO   |     |         |                |
| jointime       | int(10) unsigned    | NO   |     | 0       |                |
| createtime     | int(10) unsigned    | NO   |     | 0       |                |
| updatetime     | int(10) unsigned    | NO   |     | 0       |                |

表user2中通过uid来关联user1表

mysql水平分表和垂直分表

水平分表

垂直分表

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