method private _column_gui_update_answer = fun row_ref column input ->
    let new_name = ref None in
      if column.SQL_db.col_name <> input.CGUI.cgi_name then begin
        if not (SQL_db.validate_name input.CGUI.cgi_name) then
          raise (Invalid_input "Invalid column name");
        let found_column =
          SQL_db.column_by_name_opt
            column.SQL_db.col_table
            input.CGUI.cgi_name
        in
          if found_column <> None then
            raise (Invalid_input "Name already used");
          new_name := Some input.CGUI.cgi_name
      end;
      self#_update_column_internal row_ref column
        ?name:       !new_name
        ~comment:    input.CGUI.cgi_comment
        ~ty:         input.CGUI.cgi_type
        ~nullable:   input.CGUI.cgi_nullable
        ~options:    input.CGUI.cgi_options
        ~spec_ty:    input.CGUI.cgi_spec_ty
        ~ocaml_type: input.CGUI.cgi_ocaml_type
        ~sql2ml:     input.CGUI.cgi_sql2ml
        ~ml2sql:     input.CGUI.cgi_ml2sql
        ()