Commands:
status
status ‘simple’
status ‘detailed’
version
whoami
table_help
create ‘mytable’, ‘colfam’
list
describe ‘mytable’
disable ‘mytable’
enable ‘mytable’
disable ‘mytable’
drop ‘mytable’
table_help
show_filters
create ‘test_table’,’colfam1’
alter ‘test_table’,{NAME => ‘colfam2’}
alter ‘test_table’,{NAME => ‘colfam2’, METHOD => ‘delete’}
describe 'test_table'
alter ‘test_table’, {NAME => ‘colfam1’, VERSIONS => 2}
alter ‘test_table’, READONLY
alter 'test_table',{NAME => 'colfam2'},{NAME => 'colfam3'}
alter ‘test_table’, {NAME =>‘colfam4’, VERSIONS => 5}
alter ‘test_table’, MAX_FILESIZE => ‘1234141789’
alter_status ‘test_table’
create_namespace ‘ns1’
create ‘ns1:rt12’, ‘cf1’
list ‘ns1:rt12’
describe_namespace ‘ns1’
list_namespace
_____
create ‘f’, ‘f1’
put ‘f’, 1 , ‘f1:name’, ‘Sandeep’
put ‘f’, 1 , ‘f1:city’, ‘jal’
put ‘f’, 1 , ‘f1:id’, ‘10’
put ‘f’, 2 , ‘f1:name’, ‘XYZ’
put ‘f’, 2 , ‘f1:city’, ‘Delhi’
put ‘f’, 2 , ‘f1:id’, ‘11’
scan ‘f’
get ‘f’ , ‘1’
get ‘f’ , ‘1’, {COLUMN => ‘f1:name’}
get ‘f’ , ‘1’, {COLUMN => [‘f1:name’, ‘f1:id’]}
delete 'mytable', 1, 'colfam1:Creator' // to delete a specific cell
deleteall 'mytable','1' // to delete all the cells
count 'mytable' // to count the no. of rows
***********************PROGRAM-1 : CREATE A HBASE TABLE USING JAVA
API*****************
STEPS:
3 steps i.e.
1) specify the table name and column families
2) connect to HBase
3) create the table
USE HTableDescriptor Class to specify the tablename and column families
USE Connection Class to connect to database
USE HBaseAdmin Class to create table
USE addFamily Method to add col families
Specify col families with HColumnDescriptor
Configuration object created with HBaseConfiguration
Connection object can provide an instance of HBaseAdmin
HbaseAdmin Class contain all methods for all operations (create, delete, table)
-------------PROGRAM----------
package hBase;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import java.io.IOException;
public class createTable{
public static void main(String[] args) throws IOException {
Configuration conf=HBaseConfiguration.create();
conf.set("hbase.zookeeper.quorum", "localhost");
conf.set("hbase.zookeeper.property.clientPort", "2181");
Connection connection = ConnectionFactory.createConnection(conf);
Admin admin=connection.getAdmin();
HTableDescriptor tableName= new
HTableDescriptor(TableName.valueOf("mytable"));
tableName.addFamily(new HColumnDescriptor("colfam1"));
tableName.addFamily(new HColumnDescriptor("colfam2"));
if (!admin.tableExists(tableName.getTableName())){
System.out.print("Creating Table.");
admin.createTable(tableName);
System.out.println("Done");
}
}
}
******************************PROGRAM 2: INSERT COLUMN FOR A SINGLE ROW ID
**********************************************
put 'mytable','1','colfam1:Channel','ABC'
put 'mytable','1','colfam1:Creator','sam'
put 'mytable','1','colfam1:country','USA'
STEPS:
1) specify the row id, column and value //put class
2) connect to hbase //connection class
3) get a table object to represent our table // connection object can provide an
instance of HTABLE
4) Insert the row.
USE PUT class to specify data that will be inserted/updated.
PUT is used to insert/update a specific row id
All data that is passed to HBASE must be in the form of BYTE ARRAYS
Row id, column family names, column names, values all must be in the form of byte
arrays
BYTE CLASS is a helper class provided by HBASE to convert java primitive to BYTE
ARRAYS
USE ADD COLUMN to specify column family, column and value
IN SHELL one can insert 1 cell with 1 PUT.
------------PROGRAM--------------
package hbase;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.IOException;
public class tab2{
public static void main(String[] args) throws IOException {
Configuration conf=HBaseConfiguration.create();
Connection connection = ConnectionFactory.createConnection(conf);
Table table = connection.getTable(TableName.valueOf("mytable"));
Put put = new Put(Bytes.toBytes("1"));
put.addColumn(Bytes.toBytes("colfam1"),
Bytes.toBytes("Channel"),Bytes.toBytes("ABC"));
put.addColumn(Bytes.toBytes("colfam1"),
Bytes.toBytes("Creator"),Bytes.toBytes("Sam"));
put.addColumn(Bytes.toBytes("colfam1"),
Bytes.toBytes("Country"),Bytes.toBytes("USA"));
table.put(put);
}
}
***************************PROGRAM 3 : RETRIEVING DATA FOR A SINGLE ROW ID USING
GET() *********************************
STEPS:
STEP 1: specify the row id and column => get class help in specify
STEP 2: Connect to hbase and get a table object => Connection + HTable
STEP 3: Fetch the results
NOTE:
get method returns a result object
result is like a map ( COLUMN FAMILIES AND COLUMNS AS KEYS AND VALUES WE WANT TO
RETRIEVE AS VALUES)
getvalue method of result object acts as lookup in the map
Data in the result object is in the form of byte array
Bytes helper class has method to convert byte array to string
PROGRAM:
package hBase;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.IOException;
public class vg{
public static void main(String[] args) throws IOException {
Configuration conf=HBaseConfiguration.create();
Connection connection = ConnectionFactory.createConnection(conf);
Table table = connection.getTable(TableName.valueOf("mytable"));
// Instantiating Get Class
Get g=new Get(Bytes.toBytes("1"));
//Reading the data
Result result=table.get(g);
//Reading values from Result class object
byte []
value=result.getValue(Bytes.toBytes("colfam1"),Bytes.toBytes("Channel"));
byte []
value1=result.getValue(Bytes.toBytes("colfam1"),Bytes.toBytes("Creator"));
//printing the values
String ch=Bytes.toString(value);
String ch1=Bytes.toString(value1);
System.out.println("channel: " + ch + " creator: " + ch1);
}
}
************************PROGRAM 4: DELETE OPERATION IN HBASE TABLE USING JAVA
API****************************
STEPS:
delete 'table',1,'cf:col'
STEP 1: Specify the rowid and col
STEP 2: Connnect to HBase and get a table object
STEP 3: Delete the value
i.e. in java
Delete delete = new Delete(Bytes.toBytes("1"));
Use the delete class to specify the row,column that will be deleted.
Row Id is specified using BYTE ARRAY.
Use addcolumn to specify columns whose values should be deleted.
delete.addcolumn(Bytes.toBytes("cf"), Bytes.toBytes("col"));
We can specify any number of columns for that specific rowid.
Use the delete method to delete the value i.e.
table.delete(delete);
--------------PROGRAM----------
package hBase;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.IOException;
public class del{
public static void main(String[] args) throws IOException {
Configuration conf=HBaseConfiguration.create();
Connection connection = ConnectionFactory.createConnection(conf);
Table table = connection.getTable(TableName.valueOf("mytable"));
Delete delete=new Delete(Bytes.toBytes("1"));
delete.addColumn(Bytes.toBytes("colfam1"), Bytes.toBytes("Channel"));
table.delete(delete);
table.close();
}
}
