If populated, UpdateSelectStatement is used to create the UPDATE statement sent to your backend, so only the fields listed in that property will be updated.

>Thanks Jason. My problem solve after I change the query to select records from one table. Later I will try Me.UpdateSelectStatement.
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>I am new to MM.Net. I not really know how Me.UpdateSelectStatement works in the business object. If I use different queries in Me.FillDataSet() and Me.UpdateSelectStatement, and the fields selected are different, what will happen? Is that all the fields selected in both queries must be save to prevent any error?