anchor.diff:    }
   
     /// Executes this statement.
  +  ///
     /// If this statement contains placeholders, their values must be specified in [params].
     /// If [callback] is given, it will be invoked for each [Row] that this statement produces.
     /// [callback] may return [:true:] to stop fetching rows.
  +  ///
     /// Returns the number of rows fetched (for statements which produce rows), 
     /// or the number of rows affected (for statements which alter data).
     int execute([params = const [], bool callback(Row)]) {
  
positive.code:   }
  
    /// Creates a new reusable prepared statement.
    /// [sql] may contain '?' as a placeholder for values. These values can be
    /// specified when the statement is executed.
    /// Each prepared statement should be closed after use.
    Statement prepare(String sql) {
      _checkOpen();
  
negative.code:   }
  
    /// Executes a single SQL statement, and returns the first row.
    ///
    /// Any additional results will be discarded. If there are no results, returns null.
    Row first(String statement, [params = const []]) {
      _checkOpen();
  