Reading Data

Reading Data using HBase Shell

Using get command, you can get a single row of data at a time. Its syntax is as follows

get ’<table name>’,’row1’


The following example shows how to use the get command. Let us scan the first row of the emp table.

hbase> get 'emp', '1'

   COLUMN                     CELL
personal : city timestamp = 1217521845985, value = vijayawada
personal : name timestamp = 1217521785385, value = ashok
professional: designation timestamp = 121752125687, value = software engineer
professional: salary timestamp = 1217521902983 value = 25000

4 row(s) in 0.0270 seconds
Reading a Specific Column

Given below is the syntax to read a specific column using the get method.

hbase> get 'table name', β€˜rowid’, {COLUMN ? β€˜column family:column name ’}


Given below is the example to read a specific column in HBase table.

hbase> get 'emp', 'row1', {COLUMN ? 'personal:name'}
 COLUMN                CELL  
personal:name timestamp = 1217521785385, value = ashok
1 row(s) in 0.0060 seconds
Reading Data Using Java API
package com.ashok.hbase;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.util.Bytes;

 * @author ashok.mariyala
public class RetriveData{

   public static void main(String[] args) throws IOException, Exception{
      // Instantiating Configuration class
      Configuration config = HBaseConfiguration.create();

      // Instantiating HTable class
      HTable table = new HTable(config, "emp");

      // Instantiating Get class
      Get g = new Get(Bytes.toBytes("row1"));

      // Reading the data
      Result result = table.get(g);

      // Reading values from Result class object
      byte [] value = result.getValue(Bytes.toBytes("personal"),Bytes.toBytes("name"));

      byte [] value1 = result.getValue(Bytes.toBytes("personal"),Bytes.toBytes("city"));

      // Printing the values
      String name = Bytes.toString(value);
      String city = Bytes.toString(value1);
      System.out.println("Name: " + name + " City: " + city);

name: ashok city: Vijayawada

Reading Data

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