[TOC]
# 目录
## 全局表
### 一、描述
之前说的都是分片表，水平拆分到不同的库表。但是如果存在一个情况，不用分片的表(字典表，省份表)。
比如用户需要获取省份的数据，如果分片了，又要想办法去关联获取省份的数据，就很麻烦。<font color="red"> 使用**全局表**功能，就**只关联自己的分片库即可实现**。避免跨库这些麻烦操作！ </font>
### 二、schema.xml配置
- <font color="red"> type属性：global为全局表 </font> ，不指定则为分片表
```xml
[root@localhost bin]# cat /opt/mycat/conf/schema.xml
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="user" checkSQLschema="true" sqlMaxLimit="100">
<!-- auto sharding by id (long) -->
<table name="user" dataNode="dn246,dn247" rule="mod-long" />
<!-- 全局表 -->
<table name="province" dataNode="dn246,dn247" type="global"/>
<!-- <table name="oc_call" primaryKey="ID" dataNode="dn1$0-743" rule="latest-month-calldate"
/> -->
</schema>
<!-- <dataNode name="dn1$0-743" dataHost="localhost1" database="db$0-743"
/> -->
<dataNode name="dn246" dataHost="db246" database="user_246" />
<dataNode name="dn247" dataHost="db247" database="user_247" />
<!-- <dataNode name="dn3" dataHost="localhost1" database="db3" /> -->
<!--<dataNode name="dn4" dataHost="sequoiadb1" database="SAMPLE" />
<dataNode name="jdbc_dn1" dataHost="jdbchost" database="db1" />
<dataNode name="jdbc_dn2" dataHost="jdbchost" database="db2" />
<dataNode name="jdbc_dn3" dataHost="jdbchost" database="db3" /> -->
<dataHost name="db246" maxCon="1000" minCon="10" balance="0"
writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<!-- can have multi write hosts -->
<writeHost host="M1" url="192.168.8.246:3306" user="eddie" password="Abc@123456">
<readHost host="S1" url="192.168.8.245:3306" user="eddie" password="Abc@123456" />
</writeHost>
<!-- <writeHost host="M2" url="192.168.8.245:3306" user="eddie" password="Abc@123456"/> -->
<!-- <writeHost host="hostS1" url="localhost:3316" user="root"
password="123456" /> -->
<!-- <writeHost host="hostM2" url="localhost:3316" user="root" password="123456"/> -->
</dataHost>
<dataHost name="db247" maxCon="1000" minCon="10" balance="0"
writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<!-- can have multi write hosts -->
<writeHost host="M1" url="192.168.8.247:3306" user="eddie"
password="Abc@123456">
<!-- can have multi read hosts -->
<!-- <readHost host="hostS2" url="192.168.1.200:3306" user="root" password="xxx" /> -->
</writeHost>
<!-- <writeHost host="hostS1" url="192.168.8.247:3316" user="root"
password="123456" /> -->
<!-- <writeHost host="hostM2" url="localhost:3316" user="root" password="123456"/> -->
</dataHost>
<!--
<dataHost name="sequoiadb1" maxCon="1000" minCon="1" balance="0" dbType="sequoiadb" dbDriver="jdbc">
<heartbeat> </heartbeat>
<writeHost host="hostM1" url="sequoiadb://1426587161.dbaas.sequoialab.net:11920/SAMPLE" user="jifeng" password="jifeng"></writeHost>
</dataHost>
<dataHost name="oracle1" maxCon="1000" minCon="1" balance="0" writeType="0" dbType="oracle" dbDriver="jdbc"> <heartbeat>select 1 from dual</heartbeat>
<connectionInitSql>alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss'</connectionInitSql>
<writeHost host="hostM1" url="jdbc:oracle:thin:@127.0.0.1:1521:nange" user="base" password="123456" > </writeHost> </dataHost>
<dataHost name="jdbchost" maxCon="1000" minCon="1" balance="0" writeType="0" dbType="mongodb" dbDriver="jdbc">
<heartbeat>select user()</heartbeat>
<writeHost host="hostM" url="mongodb://192.168.0.99/test" user="admin" password="123456" ></writeHost> </dataHost>
<dataHost name="sparksql" maxCon="1000" minCon="1" balance="0" dbType="spark" dbDriver="jdbc">
<heartbeat> </heartbeat>
<writeHost host="hostM1" url="jdbc:hive2://feng01:10000" user="jifeng" password="jifeng"></writeHost> </dataHost> -->
<!-- <dataHost name="jdbchost" maxCon="1000" minCon="10" balance="0" dbType="mysql"
dbDriver="jdbc"> <heartbeat>select user()</heartbeat> <writeHost host="hostM1"
url="jdbc:mysql://localhost:3306" user="root" password="123456"> </writeHost>
</dataHost> -->
</mycat:schema>
```
### 四、重载配置
```sql
mysql> reload @@config_all;
Query OK, 1 row affected (0.24 sec)
Reload config success
```
### 五、测试
```sql
-- 192.168.8.246 和 192.168.8.247 分别运行创表DDL
CREATE TABLE `province` (
`province_id` int NOT NULL,
`province_name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
-- MyCat - 192.168.8.245 运行插入语句
INSERT INTO `user`.`province`(`province_id`, `province_name`) VALUES (10000, '广州')
-- 查看 192.168.8.246 和 192.168.8.247 是否存在 (10000, '广州') 数据
SELECT * FROM `province` WHERE `province_id` = 10000 AND `province_name` = '广州' LIMIT 1
```
> **<font color="red"> 按测试来看，那么只需要在MyCAT进行操作，就会自动同步到其他的库表。</font>**
MyCat 全局表
Copyright: 采用 知识共享署名4.0 国际许可协议进行许可
