Add tables to query build datasource in MSDAX

Add tables to query build datasource ,addlink,relation

 static void QBDSExample(Args _args)  
 {  
   Query          query;  
   QueryBuildDatasource  datasource;  
   ;  
   query = new Query();  
   // Add purchtable main datasource  
   datasource = query.addDataSource(tableNum(purchtable));  
   // Add child datasource "purchline"  
   datasource = datasource.addDataSource(tableNum(purchline));  
   // Set the join mode  
   datasource.joinMode(JoinMode::InnerJoin);  
    datasource.relations(false);  
   datasource.addLink(fieldNum(purchtable, purchid),  
     fieldNum(purchline, purchid));  
   info(query.xml());  
 }