The document provides instructions on restarting HDFS and HBase, general HBase commands, data definition and manipulation commands in HBase, and security commands like grant and revoke. It includes the syntax and examples for commands like create, list, describe, put, get, delete, scan, count, grant and revoke.

1. Steps to restart hdfs
======================
sudo service hadoop-master stop;
sudo service hadoop-master start;
hadoop dfsadmin -safemode leave;
sudo jps
Steps to restart hbase
======================
* kill hmaster,regionserver and zookeeper
* rm -Rf /usr/lib/hbase-1.1.2/logs/*
* /usr/lib/hbase-1.1.2/bin/start-hbase.sh
* hbase shell
********************************************************************************
*****************************************************
General Commands
********************************************************************************
*****************************************************
status:
======
Provides the status of HBase, for example, the number of servers.
Ex:
--
status
--------------------------------------------------------------------------------
----------------------------------------------------
version:
=======
Provides the version of HBase being used.
Ex:
--
version
--------------------------------------------------------------------------------
----------------------------------------------------
table_help:
==========
Provides help for table-reference commands.
Ex:
--
table_help
--------------------------------------------------------------------------------
----------------------------------------------------
whoami:
======
Provides information about the user.
Ex:
--
whoami
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*****************************************************
Data Definition Language
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*****************************************************
CREATE TABLE
============
Creates a table.
Syntax
------
create '<table name>','<column family>'

2. Ex
--
create 'emp', 'personal data', 'professional data'
Verification
------------
list
--------------------------------------------------------------------------------
----------------------------------------------------
LISTING TABLES
==============
Lists all the tables in HBase.
Syntax
------
list
Ex
list
--------------------------------------------------------------------------------
----------------------------------------------------
DISABLING A TABLE
=================
Disables a table.
Syntax
------
disable 'table name'
disable_all 'regex'
Ex
--
disable 'emp'
disable_all 'e.*'
Verification
------------
is_disabled 'emp'
scan 'emp'
--------------------------------------------------------------------------------
----------------------------------------------------
ENABLING A TABLE
================
Enables a table.
Syntax
------
enable 'table name'
enable_all 'regex'
Ex
--
enable 'emp'
enable_all 'e.*'
Verification
------------
is_enabled 'emp'
scan 'emp'
--------------------------------------------------------------------------------
----------------------------------------------------
DESCRIBE
========

3. Provides the description of a table.
Syntax
------
describe 'table name'
Ex
--
describe 'emp'
--------------------------------------------------------------------------------
----------------------------------------------------
ALTER
=====
Changing the Maximum Number of Cells of a Column Family
syntax
------
alter 't1', NAME => 'f1', VERSIONS => 5
Ex
--
alter 'emp', NAME => 'personal data', VERSIONS => 5
Verification
------------
describe 'emp'
--------------------------------------------------------------------------------
-----------------------------------------------------
Table Scope Operators
=====================
MAX_FILESIZE,
READONLY,
MEMSTORE_FLUSHSIZE,
DEFERRED_LOG_FLUSH
--------------------------------------------------------------------------------
-----------------------------------------------------
ALTER
=====
Table Scope Operators - Setting Read Only
syntax
------
alter 't1', READONLY(option)
Ex
--
alter 'emp', READONLY
Verification
------------
describe 'emp'
--------------------------------------------------------------------------------
-----------------------------------------------------
ALTER
=====
Table Scope Operators - Removing Table Scope Operators
syntax
------
alter 't1', METHOD => 'table_att_unset', NAME => 'MAX_FILESIZE'
Ex
--
alter 'emp', METHOD => 'table_att_unset', NAME => 'MAX_FILESIZE'

4. --------------------------------------------------------------------------------
-----------------------------------------------------
ALTER
=====
Deleting a Column Family
syntax
------
alter ' table name ', 'delete' => 'column family '
Ex
--
alter 'emp','delete'=>'professional data'
Verification
------------
describe 'emp'
--------------------------------------------------------------------------------
----------------------------------------------------
EXISTS
======
Verifies whether a table exists.
syntax
------
exists 'table name'
Ex
--
exists 'emp'
--------------------------------------------------------------------------------
----------------------------------------------------
DROP A TABLE
============
Drops a table from HBase.
syntax
------
drop 'table name'
drop_all 'regex'
Ex
--
disable 'emp'
drop 'emp'
disable_all 'e.*'
drop_all 'e.*'
Verification
------------
exists 'emp'
list
--------------------------------------------------------------------------------
----------------------------------------------------
TRUNCATE:
========
Disables, drops, and recreates a specified table.
Syntax
------
truncate 'table name'
Ex

5. --
truncate 'emp'
Verification
------------
scan 'emp'
--------------------------------------------------------------------------------
----------------------------------------------------
SHUTTING DOWN HBASE
===================
* exit the shell
Ex
--
exit
* Stopping HBase
Ex
--
./bin/stop-hbase.sh
********************************************************************************
*****************************************************
Data Manipulation Language
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CREATE DATA
===========
Puts a cell value at a specified column in a specified row in a particular
table.
Syntax
------
put '<table name>','row1','<colfamily:colname>','<value>'
Ex
--
put 'emp','1','personal data:name','raju'
put 'emp','1','personal data:city','hyderabad'
put 'emp','1','professional data:designation','manager'
put 'emp','1','professional data:salary','50000'
Verification
------------
scan 'emp'
--------------------------------------------------------------------------------
----------------------------------------------------
UPDATE DATA
===========
update an existing cell value using the put command
Syntax
------
put 'table name','row ','Column family:column name','new value'
Ex
--
put 'emp','1','personal data:city','Delhi'
Verification
------------
scan 'emp'
--------------------------------------------------------------------------------
----------------------------------------------------

6. READ DATA
=========
read a cell value using the get command
Syntax
------
get '<table name>','row1'
get 'table name', 'rowid', {COLUMN => 'column family:column name '}
Ex
--
get 'emp', '1'
get 'emp', '1', {COLUMN=>'personal data:name'}
--------------------------------------------------------------------------------
----------------------------------------------------
DELETE DATA
===========
Deletes in a table.
Syntax
------
delete '<table name>', '<row>', '<column name >', '<time stamp>'
deleteall '<table name>','<row>'
Ex
--
delete 'emp', '1', 'personal data:city', 1417521848375
deleteall 'emp','1'
Verification
------------
scan 'emp'
--------------------------------------------------------------------------------
----------------------------------------------------
HBASE SCAN
==========
Scans and returns the table data.
Syntax
------
scan '<table name>'
Ex
--
scan 'emp'
--------------------------------------------------------------------------------
----------------------------------------------------
COUNT
=====
Counts and returns the number of rows in a table.
Syntax
------
count '<table name>'
Ex
--
count 'emp'
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HBASE SECURITY
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*****************************************************
GRANT

7. =====
grant permissions to users in HBase
Syntax
------
grant <user> <permissions> [<table> [<column family> [<column qualifier>]]
R - represents read privilege.
W - represents write privilege.
X - represents execute privilege.
C - represents create privilege.
A - represents admin privilege.Ex
Ex
--
grant 'Tutorialspoint', 'RWXCA'
--------------------------------------------------------------------------------
----------------------------------------------------
REVOKE
======
used to revoke a user's access rights of a table
Syntax
------
revoke <user>
Ex
--
revoke 'Tutorialspoint'
--------------------------------------------------------------------------------
----------------------------------------------------
USER_PERMISSION
===============
list all the permissions for a particular table
Syntax
------
user_permission 'tablename'
Ex
--
user_permission 'emp'