匿名通过本文主要向大家介绍了MySQL，MyCAT，schema等相关知识,希望本文的分享对您有所帮助
在第一部分，有简单的介绍MyCAT的搭建和配置文件的基本情况，这一篇详细介绍schema的一些具体参数，以及实际作用
首先贴上自己测试用的schema文件，双引号之前的反斜杠不会消除，姑且当成不存在吧...
首先贴上自己测试用的schema文件，双引号之前的反斜杠不会消除，姑且当成不存在吧...
<?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> 第一行参数<schema name="mycat" checkSQLschema="false" sqlMaxLimit="100"/>
在这一行参数里面,schema name定义了可以在MyCAT前端显示的逻辑数据库的名字