cassandra - 查询以读取 cassandra hector 中的复合列

Question

我需要根据行键读取 cassandra 列族中的所有值。我只得到一个行键。我想查询列族中的所有键。

列族的架构

rowKey 是字符串，值在列名本身中，例如 date:subject:marks 即在 db 2013-04-13 00:00:00 UTC,science,99 中保存为 rowkey=1

像这样尝试

  Cluster cluster = HFactory.getOrCreateCluster("Test Cluster", "localhost:9160");
  Keyspace keyspaceOperator = HFactory.createKeyspace(student, cluster);
  System.out.println( "Connected to cassandra " + cluster);
  String rowKey = "1";


  SliceQuery<String,String,String> columnQuery = HFactory.createSliceQuery(keyspaceOperator, StringSerializer.get(), StringSerializer.get(), StringSerializer.get());
  columnQuery.setColumnFamily("studentInfo").setKey(rowKey).setRange(null, null, false, 100);
  System.out.println(columnQuery);
  QueryResult<ColumnSlice<String,String>> result = columnQuery.execute();
  for (HColumn<String, String> column : result.get().getColumns()) {
    System.out.println(column.getName());
  }

Answer 1

你可以试试这个？？？

      SliceQuery<String,String,String> columnQuery = HFactory.createSliceQuery(ksp, StringSerializer.get(), StringSerializer.get(), StringSerializer.get());
      columnQuery.setColumnFamily("studentInfo").setKey(rowKey).setColumnNames("id","name");
      QueryResult<ColumnSlice<String,String>> result = columnQuery.execute();