Parent Columns and Child Columns don't have type-matching columns.

HI
i am making  relation between two datatables and m getting this error
in this ds.Tables(0).Columns("In_ID") datatype is string
ds.Tables(1).Columns("row_id") datatype is integer
how i do the type casting here to make dataset relation

ds.Relations.Add("Rel_1", ds.Tables(0).Columns("In_ID"), ds.Tables(1).Columns("row_id"), True)






...