Query to read on composite columns in cassandra hector

Question

I need to read all values in a cassandra column family according to the row key. I am getting only for one row key. I want to query for all the keys in the column family.

Schema of the column family

rowKey is String and the values are in the column names itself like date:subject:marks i.e saved like this in the db 2013-04-13 00:00:00 UTC,science,99 for rowkey=1

trying like this

  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());
  }

score 0 · Answer 1 · answered Jul 15 '13 at 11:01

0

Can you try this???

      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();

answered Jul 15 '13 at 11:01

abhi

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yes this works but only for one row i am not able to iterate over all rows in the keyspace.. Also columns in my keyspace dont have a label they are saved in column names like `1 | 2013-04-01,science,96` – Shalu Jul 15 '13 at 11:06
do you mean a single column whose value is like 2013-04-01,science,96 – abhi Jul 15 '13 at 11:30
Also in your question, code snippet, you want to know the result corresponding to a single rowKey. I am not getting the whole thing properly. Need to be clarified – abhi Jul 15 '13 at 11:33
See this is the column family structure in my app ` rowkey studentinfo 1 | 2013-04-01,science,96 2 | 2013-04-01,science,96 | 2013-04-02,maths,96 | 2012-04-03,english,90` I want to query row by row on each column – Shalu Jul 15 '13 at 11:59
`rowkey studentinfo` `1 | 2013-04-01,science,96` `2 | 2013-04-01,science,96 | 2013-04-02,maths,96 | 2012-04-03,english,90` – Shalu Jul 15 '13 at 12:02
@abhi, I also have similar question [here](http://stackoverflow.com/questions/18921964/composite-column-values-in-cassandra). Can you please take a look? – arsenal Sep 21 '13 at 00:13

Query to read on composite columns in cassandra hector

1 Answers1