Wang Tong,

>2. For the second question, we try to prevent our application from deleting a record if the record is referenced in other child table. For example, there 2 tables, customer and order. Customer table is the parent table. Order table is child table. The relationship is one to many, which means customer can have many orders. If a customer has order record in order table, our application will prevent user from deleting this record. We can do this by using cascade DELETEs or UPDATEs in database. Does MM.Net provide better way of handling this scenario?

Yes...in the business object's HookPreDelete() method you can place code that checks if there are any existing records that would prevent a delete, then abandon the delete if so.

Best Regards,