<connectionStrings>

<!--从PRIMARY库读取，会立即显示最新数据-->

<add name="PattayaDBConnection" connectionString="mongodb://username:xxxxxxx@IP1,IP2,IP3,IP4/DBname?replicaSet=rs_main&amp;readPreference=primary" />

<!--从SECONDARY库读取-->

<add name="Pattaya.ProductMongoDbProvider.ProductDB" connectionString="mongodb://username:xxxxxxx@IP1,IP2,IP3,IP4/DBname?replicaSet=rs_main&amp;readPreference=secondaryPreferred" />

<!--没有readPreference参数是只写，不用读-->

<add name="PattayaMallHistoryConnection" connectionString="mongodb://username:xxxxxxx@IP1,IP2,IP3,IP4/DBname?replicaSet=rs_main" />

</connectionStrings>

注：在HTML中的&用&amp;来表示