mycat之schema.xml理解

    <?xml version="1.0"?>
    <!DOCTYPE mycat:schema SYSTEM "schema.dtd">
    <mycat:schema xmlns:mycat="http://org.opencloudb/">

        <schema name="mycat" checkSQLschema="false" sqlMaxLimit="100">
            <!-- auto sharding by id (long) -->
            <table name="students" dataNode="dn1,dn2,dn3,dn4" rule="rule1" />
            <table name="log_test" dataNode="dn1,dn2,dn3,dn4" rule="rule2" />
            <!-- global table is auto cloned to all defined data nodes ,so can join
                with any table whose sharding node is in the same data node -->
            <!--<table name="company" primaryKey="ID" type="global" dataNode="dn1,dn2,dn3" />
            <table name="goods" primaryKey="ID" type="global" dataNode="dn1,dn2" />
                -->
            <table name="item_test" primaryKey="ID" type="global" dataNode="dn1,dn2,dn3,dn4" />
            <!-- random sharding using mod sharind rule -->
            <!-- <table name="hotnews" primaryKey="ID" dataNode="dn1,dn2,dn3"
                rule="mod-long" /> -->
                <!--
            <table name="worker" primaryKey="ID" dataNode="jdbc_dn1,jdbc_dn2,jdbc_dn3" rule="mod-long" />
     -->
            <!-- <table name="employee" primaryKey="ID" dataNode="dn1,dn2"
                rule="sharding-by-intfile" />
            <table name="customer" primaryKey="ID" dataNode="dn1,dn2"
                rule="sharding-by-intfile">
                <childTable name="orders" primaryKey="ID" joinKey="customer_id"
                    parentKey="id">
                    <childTable name="order_items" joinKey="order_id"
                        parentKey="id" />
                <ildTable>
                <childTable name="customer_addr" primaryKey="ID" joinKey="customer_id"
                    parentKey="id" /> -->
        </schema>

        <!-- <dataNode name="dn" dataHost="localhost" database="test" /> -->
        <dataNode name="dn1" dataHost="localhost" database="test1" />
        <dataNode name="dn2" dataHost="localhost" database="test2" />
        <dataNode name="dn3" dataHost="localhost" database="test3" />
        <dataNode name="dn4" dataHost="localhost" database="test4" />
        <!--
        <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="localhost" maxCon="100" minCon="10" balance="1"
            writeType="1" dbType="mysql" dbDriver="native">
            <heartbeat>select user()<beat>
            <!-- can have multi write hosts -->
            <writeHost host="localhost" url="localhost:3306" user="root" password="wangwenan">
                <!-- can have multi read hosts -->
                <readHost host="hostS1" url="localhost:3307" user="root" password="wangwenan"/>
            </writeHost>
            <writeHost host="localhost1" url="localhost:3308" user="root" password="wangwenan">
                <!-- can have multi read hosts -->
                <readHost host="hostS11" url="localhost:3309" user="root" password="wangwenan"/>
            </writeHost>
        </dataHost>
            <!-- <writeHost host="hostM2" url="localhost:3316" user="root" password="123456"/> -->
        <!--
            <dataHost name="jdbchost" maxCon="1000" minCon="1" balance="0" writeType="0" dbType="mongodb" dbDriver="jdbc">
            <heartbeat>select user()<beat>
            <writeHost host="hostM" url="mongodb://192.168.0.99/test" user="admin" password="123456" ></writeHost>
        </dataHost>    
        -->
         <!--
        <dataHost name="jdbchost" maxCon="1000" minCon="10" balance="0"
            dbType="mysql" dbDriver="jdbc">
            <heartbeat>select user()<beat>
            <writeHost host="hostM1" url="jdbc:mysql://localhost:3306"
                user="root" password="123456">
            </writeHost>
        </dataHost>
         -->
    </mycat:schema>

参考：这几篇文章还是写的不错，都是一个系列的

http://blog.itpub.net/29510932/viewspace-1664499/  基础讲解

http://blog.itpub.net/29510932/viewspace-1667814/  配置文件schema.xml讲解

http://blog.itpub.net/29510932/viewspace-1678591/  分表规则