# File lib/rubyrep/connection_extenders/jdbc_extender.rb, line 19
      def primary_key_names(table)
        if tables.grep(/^#{table}$/i).empty?
          # Note: Cannot use tables.include? as returned tables are made lowercase under JRuby MySQL
          raise "table '#{table}' does not exist"
        end
        columns = []
        result_set = @connection.connection.getMetaData.getPrimaryKeys(nil, nil, table);
        while result_set.next
          column_name = result_set.getString("COLUMN_NAME")
          key_seq = result_set.getShort("KEY_SEQ")
          columns << {:column_name => column_name, :key_seq => key_seq}
        end
        columns.sort! {|a, b| a[:key_seq] <=> b[:key_seq]}
        key_names = columns.map {|column| column[:column_name]}
        key_names
      end