Unique ID

[NaNg]

Hey, I don't realy know where to post this, so I'm gonna post it in here and in XML forum.This is my problem:I have a XML with DataSet in it, in the DataSet I have 2 DataTables, in each DataTable I have a Unique ID, and I did to this row, auto-inc, and don't allow DBNull, and it's readonly.So when I try to do NewRow(), and add it without setting the ID column, it throws an Exception DataColumn 'ID' can't allow DBNull.So how can I do it as UNIQUE ID? do I need to allow DBNull?Another thing I wanted to ask, which of the two (XML\XSL) contains the Data?I mean when I have a DataSet ds, what do I need to do to save the DATA?ds.WriteXml() or ds.WriteXmlSchema()? (same thing about reading.)Thanks in advanced...NaNg.