anchor.diff:    )
     """],
     (String stmt) => conn.execute(stmt));
  -
  -Future cleanDB(Connection conn)
  -=> Future.forEach(const ['"Detail"', '"Master"'],
  -  (String otype) => conn.execute("drop table $otype"));
  
positive.code:   })
    .whenComplete(() {
      if (conn != null) {
        return cleanDB(conn)
        .then((_) => conn.close())
        .catchError((ex, st) => print("Error ${ex.runtimeType}: $ex\n$st"));
      } else {
        print("Make sure you create a case-sensitive database called testdb, "
          "and the password must be 123");
  
negative.code: Future initDB(Connection conn)
  => Future.forEach(const [
    """
    create temporary table "Master" (
      "oid" varchar(40) primary key,
      "name" varchar(60)
    )
    """, """
    create temporary table "Detail" (
      "oid" varchar(40) primary key,
      "createdAt" timestamp without time zone null,
      "value" integer,
  