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Tuesday, 14 March 2017

HBase Delete Data Tutorial


Deleting a Specific Cell in a Table
     Using the delete command, you can delete a specific cell in a table. The syntax of delete command is as follows
delete ‘<table name>’, ‘<row>’, ‘<column name >’, ‘<time stamp>’
Example
     Here is an example to delete a specific cell. Here we are deleting the salary.
hbase> delete 'emp', '1', 'personal data:city', 1217521785385
0 row(s) in 0.0050 seconds
Deleting All Cells in a Table
     Using the “deleteall” command, you can delete all the cells in a row. Given below is the syntax of deleteall command.
deleteall ‘<table name>’, ‘<row>’,
Example
     Here is an example of “deleteall” command, where we are deleting all the cells of row1 of emp table.
hbase> deleteall 'emp','1'
0 row(s) in 0.0420 seconds
Deleting Data Using Java API
package com.ashok.hbase;

import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.util.Bytes;

public class DeleteData {

   public static void main(String[] args) throws IOException {

      // Instantiating Configuration class
      Configuration conf = HBaseConfiguration.create();

      // Instantiating HTable class
      HTable table = new HTable(conf, "employee");

      // Instantiating Delete class
      Delete delete = new Delete(Bytes.toBytes("row1"));
      delete.deleteColumn(Bytes.toBytes("personal"), Bytes.toBytes("name"));
      delete.deleteFamily(Bytes.toBytes("professional"));

      // deleting the data
      table.delete(delete);

      // closing the HTable object
      table.close();
      System.out.println("Data deleted successfully...!!");
   }
}

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