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Cassandra Read Operation

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by , 02-23-2012 at 06:17 PM (952 Views)
For example we have a number of authors in the database and we want to read them in Java. Below code explains this operation in detail.
Java Code: This is the code to Cassandra Read Operation
import org.apache.cassandra.thrift.SlicePredicate;
import org.apache.cassandra.thrift.SliceRange;
import org.apache.cassandra.thrift.ColumnOrSuperColumn;
import org.apache.cassandra.thrift.ColumnParent;
import org.apache.cassandra.thrift.ConsistencyLevel;
...
SlicePredicate slicePredicate = new SlicePredicate();
SliceRange sliceRange = new SliceRange();
sliceRange.setStart(new byte[] {});
sliceRange.setFinish(new byte[] {});
slicePredicate.setSlice_range(sliceRange);
List result = client.get_slice("Blog", "Ronald Mathies", new ColumnParent("Authors"), slicePredicate, ConsistencyLevel.ONE);
In the above code SlicePredicate is created that informs Cassandra about the data fetch. In the above code, a range of columns are fetched. setStart() and setFinish() use name attributes to fetch the data. An empty byte array is passed.

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