WCF / ASMX :: Data Contract (consume By Sliverlight Application)

I have a lot confusion on data contract .I think Data contract will create according to the Service contract and Data Base Table. For Example Let say i have service contract and i have three table product,order,customer

[ServiceContract]
public interface IMembersService
{
[OperationContract]
void insertProductDetails(clsProduct objProduct);
//What about the return type can we make it bool
[OperationContract]
List<clsProduct> getproductInfoByID(int id);
[OperationContract]
List<clsProduct> getproductInfo();
//========================================
[OperationContract]
void insertOrderDetails(clsOrder objOrder);
//What about the return type can we make it bool
[OperationContract]
List<clsOrder> getOrderInfoByID(int id);
[OperationContract]
List<clsOrder> getOrderInfo();
//========================================
[OperationContract]
void insertCustomerDetails(clsOrder objOrder);
//What about the return type can we make it bool
[OperationContract]
List<clsOrder> getCustomerInfoByID(int id);
[OperationContract]
List<clsOrder> getCustomerInfo();
}

For this case can i create three datacontact clsProduct,clsOrder,clsCustomer .i mean data contact depends on ther service contact and the table.