There's a little bit of a trick to this, which is to add the fields
you want before opening the table.  Something like this:

var F : TField;
begin
  if Table1.Active then Table1.Close;
  Table1.FieldDefs.Update;
  F := TStringField.Create(Self);
  F.Name := 'afield';
  F.FieldName := 'afield';
  F.FieldKind := fkData;
  F.Size := 20; // or whatever, but should match underlying table
                // field
  F.DataSet := Table1;

Fwiw, this works even if you have persistent fields defined, and with
TQueries.

Cheers, Martyn

Table1.FieldDefs.Add(fieldname, fieldtype, fieldsize, required);

and you have made a field at runtime!! Congratulations! heheh

Nirav Kaku