def replace data_hash = {}
    sql, *binds = SQLHelper.replace :table => name,
                                    :data => @query_default.merge(data_hash),
                                    :prepared => true
    pstmt = prepare :insert, sql
    pstmt.send @update_method, *binds
  end
def replace data_hash = {}
    sql, *binds = SQLHelper.replace :table => name,
                                    :data => @query_default.merge(data_hash),
                                    :prepared => true
    pstmt = prepare :insert, sql
    pstmt.send @update_method, *binds
  end
Replaces a record in the table with the new one with the same unique key.
 @note This is not SQL standard. Only works if the database supports replace syntax.
 @param [Hash] data_hash Column values in Hash
 @return [Fixnum] Number of affected records