Exactly. I define a pair of DTOs for each virtual table: an input type (the shape of a record that can be inserted) and an output one (the shape of each record

Exactly. I define a pair of DTOs for each virtual table: an input type (the shape of a record that can be inserted) and an output one (the shape of each record returned when you select from the virtual table, which might include generated, computed, and foreign columns, etc). These types do not necessarily have to map to the underlying table types.