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From Apache Wiki <wikidi...@apache.org>
Subject [Lucene-hadoop Wiki] Update of "Hbase/HbaseShell" by udanax
Date Thu, 03 Jan 2008 03:31:26 GMT
Dear Wiki user,

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The following page has been changed by udanax:
http://wiki.apache.org/lucene-hadoop/Hbase/HbaseShell

------------------------------------------------------------------------------
  ||Delete ||'''Delete''' command deletes specified rows in table. [[BR]][[BR]]~-''DELETE
{ column_name, [, column_name] ... | COLUMNFAMILIES(column_family[, column_family] ... | *}
[[BR]]{{{    }}}FROM table_name[[BR]]{{{    }}}[WHERE row = 'row-key'];''-~ ||
  ||Select ||<99%>'''Select''' command retrieves rows from a table.[[BR]][[BR]]~-''SELECT
{ column_name [, column_name] ... | * }[[BR]]{{{    }}}FROM table_name[[BR]]{{{    }}}[WHERE
row = 'row-key' | STARTING FROM 'row-key'][[BR]]{{{    }}}[NUM_VERSIONS = version_count][[BR]]{{{
   }}}[TIMESTAMP 'timestamp'][[BR]]{{{    }}}[LIMIT = row_count][[BR]]{{{    }}}[INTO FILE
'file_name'][[BR]][[BR]]''-~'''column_name:'''~-''[[BR]]{{{     }}}column_family_name[[BR]]{{{
   }}}| column_family_name:column_label_name''-~ ||
  
+ = Examples =
+ == Example Of Basic Query Command Uses ==
+ === Create the table in a Hbase ===
+ 
+ {{{
+ hql > help create;
+ CREATE    Create tables
+ 
+ Syntax:
+ CREATE TABLE table_name
+         column_family_definition [, column_family_definition] ...
+ 
+ column_family_definition:
+         column_family_name
+         [MAX_VERSIONS=n]
+         [MAX_LENGTH=n]
+         [COMPRESSION=NONE|RECORD|BLOCK]
+         [IN_MEMORY]
+         [BLOOMFILTER=NONE|BLOOMFILTER|COUNTING_BLOOMFILTER|RETOUCHED_BLOOMFILTER VECTOR_SIZE=n
NUM_HASH=n]
+ }}}
+ 
+ '''CREATE TABLE''' enables you to create a new table with various options for each column
family.
+ 
+  * ~-'''MAX_VERSIONS''' makes a table keep only the recent n versions in a cell. Its default
value is 3, i.e., only the most recent 3 versions of values are stored in a cell.-~
+  * ~-'''MAX_LENGTH''' specifies the maximum size of a column value. By default, the maximum
size is unlimited. It is limited only by Integer.MAX_VALUE.-~
+  * ~-'''COMPRESSION''' specifies which compression technique to use for the column family.
By default, Hbase does not compress any data.-~
+  * ~-'''IN_MEMORY''' specifies whether to keep the values in the column family in-memory,
or not. By default, values are not kept in-memory.-~
+  * ~-'''BLOOMFILTER''' specifies which bloom filter to use for the column family. By default,
none of the bloom filters is used. You can specify the options in two ways: with '''VECTOR_SIZE'''
and '''NUM_HASH''', or with '''NUM_ENTRIES'''. '''VECTOR_SIZE''' specifies the number of elements
in the vector, and '''NUM_HASH''' specifies the number of hash functions to use; With '''NUM_ENTRIES''',
you  specify only the approximated number of entries in the column, and '''VECTOR_SIZE'''
and '''NUM_HASH''' are automatically determined.-~
+ 
+ {{{
+ hql > CREATE TABLE movieLog_table (
+   --> year, length, inColor, studioName, vote, producer, actor)
+   --> NUM_VERSIONS 10; 
+ 
+ hql > CREATE TABLE webtable (
+   --> contents in_memory max_versions=10 compression=block,
+   --> anchor max_length=256 bloomfilter=counting_bloomfilter
+   --> vector_size=1000000 num_hash=4);
+ }}}
+ 
+ === Select data from a table ===
+ {{{
+ hql > help select;
+ SELECT    Select values from tables
+ 
+ Syntax:
+ SELECT { column_name, [, column_name] ... | *} FROM table_name
+         [WHERE row='row_key' | STARTING FROM 'row-key']
+         [NUM_VERSIONS = version_count]
+         [TIMESTAMP 'timestamp']
+         [LIMIT = row_count]
+         [INTO FILE 'file_name']
+ }}}
+ 
+ '''SELECT''' retrieves a subset of data from the specified table.
+ 
+  * ~-'''STARTING FROM''' returns all the rows starting from 'row-key'.-~
+  * ~-'''NUM_VERSIONS''' retrieves only the recent n versions of values in a cell.-~
+  * ~-'''TIMESTAMP''' returns only the values with the specified timestamp.-~
+  * ~-'''LIMIT''' limits the number of rows to be returned.-~ 
+ 
+ {{{
+ hql > SELECT studioName: FROM movieLog_table WHERE row = 'Star Wars';
+ 
+ +---------------------------------------------+
+ | title         studioName                    |
+ | =========================================== |
+ | Star Wars     Fox Entertainment Group, Inc. |
+ +---------------------------------------------+
+ 
+ Successfully print out the selected data.(0.05 sec)
+ 
+ hql > SELECT 'studioName:YoungGu Art, Corp.' FROM movieLog_table WHERE row = 'D-War';
+ }}}
+ 
+ === Insert data into a table ===
+ {{{
+ hql > help insert;
+ INSERT    Insert values into tables
+ 
+ Syntax:
+ INSERT INTO table_name
+         (colmn_name, ...) VALUES ('value', ...)
+         WHERE row='row_key'
+ 
+ column_name:
+           column_family_name
+         | column_family_name:column_label_name
+ }}}
+ 
+ '''INSERT''' inserts a set of values into a table. 
+ 
+  * ~-If the specified column already exists, the new value is stored as a new version.-~
+  * ~-If '''TIMESTAMP''' is not specified for the value, the current time is used as its
timestamp.-~
+ 
+ {{{
+ hql > INSERT INTO movieLog_table (year:, length:, inColor:, studioName:, 'vote:user name',
producer:, 'actor:hero')
+   --> VALUES ('1977', '124', 'true', 'Fox', '5', 'George Lucas', 'Mark Hamill')
+   --> WHERE row='Star Wars';
+ }}}
+ 
+ === Delete data in a table ===
+ {{{
+ hql > help delete;
+ DELETE    Delete table data
+ 
+ Syntax:
+ DELETE { column_name, [, column_name] ... | COLUMNFAMILIES(column_family[, column_family]
... | *} 
+         FROM table_name
+         [WHERE row = 'row-key'];
+ }}}
+ 
+  * Asterisk (*) will be delete the all in table.
+  * COLUMNFAMILIES(column_family list) will be delete the all columns in columnfamily.
+  * Specified column_name will be delete the specified column data.
+ 
+ {{{
+ hql > DELETE actor:hero FROM movieLog_table;
+ hql > DELETE actor:hero FROM movieLog_table WHERE row='Star Wars';
+ hql > DELETE * FROM movieLog_table;
+ }}}
+ 
+ === How to use external jars in Hbase Shell ===
+ 
+ {{{
+ hql > HELP JAR;
+ JAR jarFile [mainClass] args...;
+ ...
+ 
+ hql > JAR ./build/hadoop-examples.jar pi 10 10;
+ }}}
+ 

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