Thanks. Tamar
On January 23, 2012 at 11:24 AM aaron morton <aa...@thelastpickle.com> wrote: > The columns are stored at the intersection of the row and the CF. So if you > read all the columns for a row in a CF you are only getting those ones. > > Your hector code (using the range) looks correct to me. > > Have fun. > Aaron > > > > > > > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > > On 23/01/2012, at 9:24 PM, Tamar Fraenkel wrote: > > > > > > > Hi! > > > > I am getting started with Cassandra and Hector and have a question. > > If I have CF with many columns, only a small portion of them having values > > for any given key. I want to read all columns for a given key, but I don't > > know which columns were populated. > > I managed to do that with the code below (assumes that column names are > > incremental numbers). > > Is there any better way? > > Thanks, > > Tamar > > private static void readAllColunsForRowKey(String key) { > > MultigetSliceQuery<String, Long, String> multigetSlicesQuery = > > HFactory.createMultigetSliceQuery(tutorialKeyspace, > > StringSerializer.get(), LongSerializer.get(), > > StringSerializer.get()); > > multigetSlicesQuery.setColumnFamily(CF); > > multigetSlicesQuery.setKeys(key); > > multigetSlicesQuery.setRange(null, null, false, COL_COUNT); > > QueryResult<Rows<String, Long, String>> results = > > multigetSlicesQuery.execute(); > > Long lastColName; > > while ((lastColName = printColsAndGetLastColName(results, key)) != null) { > > multigetSlicesQuery.setRange(lastColName + 1, null, false, COL_COUNT); > > results = multigetSlicesQuery.execute(); > > } > > } > > > > private static Long printColsAndGetLastColName(QueryResult<Rows<String, > > Long, String>> results, String key) { > > Rows<String, Long, String> rows = results.get(); > > if (rows.getCount() != 1) { > > System.out.println("No such key"); > > return null; > > } > > Row<String, Long, String> row = rows.getByKey(key); > > ColumnSlice<Long, String> columnSlice = row.getColumnSlice(); > > List<HColumn<Long, String>> columns = columnSlice.getColumns(); > > for (HColumn<Long, String> column : columns) { > > System.out.println("Column Name: " + column.getName() > > + ", Column Val: " + column.getValue()); > > } > > if (columns.size() == COL_COUNT) { > > return columns.get(COL_COUNT - 1).getName(); > > } > > return null; > > } > >
