数据库中间件mycat安装与使用详解数据库

# wget http://dl.mycat.io/1.6-RELEASE/Mycat-server-1.6-RELEASE-20161028204710-linux.tar.gz

# tar -zxvf ~/Mycat-server-1.6-RELEASE-20161028204710-linux.tar.gz -C /usr/local

# cd /usr/local/mycat/conf 
# vim schema.xml

<?xml version="1.0"?> 
<!DOCTYPE mycat:schema SYSTEM "schema.dtd"> 
<mycat:schema xmlns:mycat="http://io.mycat/">
<!--schema 数据库-->
 
    <schema name="testMyCat" checkSQLschema="false" sqlMaxLimit="100">
<!--table 表名-->
 
        <table name="order"  type="global" dataNode="order" /> 
        <table name="orderDetail"  type="global" dataNode="orderDetail" /> 
        <table name="commodity"  type="global" dataNode="order" /> 
    </schema>
<!---datanode数据节点，database对应各个datahost中的数据库名，datahost用于配置数据库服务器地址->
 
    <dataNode name="order" dataHost="host2" database="jxtest" /> 
    <dataNode name="orderDetail" dataHost="host1" database="usercenter" /> 
    <dataHost name="host1" maxCon="1000" minCon="10" balance="0" 
              writeType="0" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100"> 
        <heartbeat>select user()</heartbeat> 
        <writeHost host="hostM1" url="192.168.3.30:3306" user="root" password="[email protected]^&amp;*()" /> 
    </dataHost> 
    <dataHost name="host2" maxCon="1000" minCon="10" balance="0" 
              writeType="0" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100"> 
        <heartbeat>select user()</heartbeat> 
        <writeHost host="hostM2" url="192.168.3.62:4000" user="root" password="" /> 
    </dataHost> 
</mycat:schema>

# vim server.xml       #然后找到user节点配置

<user name="root"> 
        <property name="password">123456</property> 
        <property name="schemas">testMyCat</property> 
    </user>
<!--user.name登陆用户名，password登录密码，schemas该用户可使用的数据库名，testMayCat对应schema.xml文件中配置的schema-->

# cd /usr/local/mycat/bin 
# ./mycat start

# ./mycat status 
Mycat-server is running (29287).

/*!mycat:catlet=io.mycat.catlets.ShareJoin */ 
SELECT 
* 
FROM t_order t 
INNER JOIN order_detail td ON t.orderId = td.orderId

/*!mycat:catlet=io.mycat.catlets.ShareJoin */ 
SELECT 
* 
FROM t_order t 
INNER JOIN order_detail td ON t.orderId = td.orderId 
INNER JOIN commodity c ON td.commodityId = c.id