Apache HBase DML Commands

HBase - DDL Commands

HBase - Admin API

DML commands are used to perform data manipulation operations such as putting data into a table, retrieving data from a table and deleting schema, and so on.

Apache HBase supports the below list of DML commands.

1. Put
2. Count
3. Get
4. Scan
5. Delete
6. Delete all
7. Truncate

Let us see each DML command in detail.

1. Put

Put command is used to insert data in a table

To perform the Put operation, we will create a table with the name "employee" and insert data.

The structure of the table should look like below.

Syntax

hbase(main):015:0> put <'tablename'>,<'rowname'>,<'columnvalue'>,<'value'>

Command

hbase(main):015:0> create 'employee','emp_contact_data','emp_professional_data'

hbase(main):016:0> put 'employee','1','emp_contact_data:first_name','James'

hbase(main):017:0> put 'employee','1','emp_contact_data:last_name','Butt'

hbase(main):018:0> put 'employee','1','emp_contact_data:city','New Orleans'

hbase(main):019:0> put 'employee','1','emp_contact_data:county','Orleans'

hbase(main):020:0> put 'employee','1','emp_professional_data:designation','manager'

hbase(main):021:0> put 'employee','1','emp_professional_data:salary','100000'

hbase(main):022:0> put 'employee','2','emp_contact_data:first_name','Josephine'

hbase(main):023:0> put 'employee','2','emp_contact_data:last_name','Darakjy'

hbase(main):024:0> put 'employee','2','emp_contact_data:city','Brighton'

hbase(main):025:0> put 'employee','2','emp_contact_data:county','Livingston'

hbase(main):026:0> put 'employee','2','emp_professional_data:designation','associate'

hbase(main):027:0> put 'employee','2','emp_professional_data:salary','50000'

hbase(main):029:0> put 'employee','3','emp_contact_data:first_name','Art'

hbase(main):030:0> put 'employee','3','emp_contact_data:last_name','Venere'

hbase(main):031:0> put 'employee','3','emp_contact_data:city','Bridgeport'

hbase(main):032:0> put 'employee','3','emp_contact_data:county','Gloucester'

hbase(main):033:0> put 'employee','3','emp_professional_data:designation','developer'

hbase(main):034:0> put 'employee','3','emp_professional_data:salary','60000'

hbase(main):035:0> put 'employee','4','emp_contact_data:first_name','Lenna'

hbase(main):036:0> put 'employee','4','emp_contact_data:last_name','Paprocki'

hbase(main):037:0> put 'employee','4','emp_contact_data:city','Anchorage'

hbase(main):038:0> put 'employee','4','emp_contact_data:county','Anchorage'

hbase(main):039:0> put 'employee','4','emp_professional_data:designation','Sr Developer'

hbase(main):040:0> put 'employee','4','emp_professional_data:salary','65000'

hbase(main):041:0> put 'employee','5','emp_contact_data:first_name','Simona'

hbase(main):042:0> put 'employee','5','emp_contact_data:last_name','Morasca'

hbase(main):043:0> put 'employee','5','emp_contact_data:city','Ashland'

hbase(main):044:0> put 'employee','5','emp_contact_data:county','Ashland'

hbase(main):045:0> put 'employee','5','emp_professional_data:designation','executive'

hbase(main):046:0> put 'employee','5','emp_professional_data:salary','45000'

Output

2. Count

The count command is used to count the number of rows present in a table. Using the “Cache” option we can restrict the row which should be displayed. The default size of “Cache” is 10 rows.

Syntax

hbase(main):047:0> count <'tablename'>, CACHE =>1000

Command

hbase(main):047:0> count 'employee'

The below command is fetching 1000 rows at a time. In the output, the result is showing only five rows because there are only five rows present in table “employee”.

Output

3. Get

Get command is used to read data from a table.

Using the get command, we can read a single row of data at a time.

Syntax

hbase(main):051:0> get ’<table name>’,’row1’

Command

hbase(main):051:0> get 'employee', '1'

Output

We can read a specific column as well using the ‘get’ command.

Syntax

hbase(main):052:0> get 'table name', ‘rowid’, {COLUMN ⇒ ‘column family:column name ’}

Command

hbase(main):058:0> get 'employee','1',{COLUMN => 'emp_contact_data:first_name'}

Output

4. Scan

Scan command is used to view the complete data of a table “employee”.

Syntax

hbase(main):059:0> scan ‘<table name>’

Command

hbase(main):059:0> scan 'employee'

Output

5. Delete

Delete command is used to delete a specific cell in a table.

Syntax

hbase(main):001:0>delete ‘<table name>’, ‘<row>’, ‘<column name >’, ‘<time stamp>’

In this example, we are deleting a specific cell.

Command

hbase(main):002:0>delete 'employee', '1', 'emp_professional_data:salary'

Output

6. Deleteall

Delete all command is used to delete all cells in a row.

Syntax

hbase(main):003:0> deleteall ‘<table name>’, ‘<row>’

In this example, we are deleting all cells in a row.

Command

hbase(main):003:0> deleteall 'employee', '1'

Output

7. Truncate

The truncate command is used to delete all rows and columns in a table. It will delete only data and not the structure of the table.

Syntax

hbase(main):004:0> truncate <tablename>

Command

hbase(main):004:0> truncate 'employee'

Output