這里我們用一個學生成績表作為例子,對HBase的基本操作和基本概念進行講解:

下面是學生的成績表:
name grad? ?? ?course:math? ?course:art
Tom? ? 1? ? ? ?? ?? ?? ?87? ?? ?? ?? ?? ?? ???97

Jerry? ?2? ?? ?? ?? ?100? ?? ?? ?? ?? ?? ?80

? ? ? ? 這里grad對于表來說是一個列,course對于表來說是一個列族,這個列族由兩個列組成:math和art,當然我們可以根據我們的需要在course中建立更多的列族,如computer,physics等相應的列添加入course列族.

? ? ? ? 有了上面的想法和需求,我們就可以在HBase中建立相應的數據表啦!

1, 建立一個表格 scores 具有兩個列族grad 和courese

hbase(main):002:0> create 'scores', 'grade', 'course'

0 row(s) in 4.1610 seconds

2,查看當先HBase中具有哪些表

hbase(main):003:0> list

scores

1 row(s) in 0.0210 seconds

3,查看表的構造

hbase(main):004:0> describe 'scores'

{NAME => 'scores', IS_ROOT => 'false', IS_META => 'false', FAMILIES => [{NAME => 'course', BLOOMFILTER => 'false', IN_MEMORY => 'false', LENGTH => '2147483647', BLOCKCACHE => 'false', VERSIONS => '3', TTL => '-1', COMPRESSION => 'NONE'}, {NAME => 'grade', BLOOMFILTER => 'false', IN_MEMORY => 'false', LENGTH => '2147483647', BLOCKCACHE => 'false', VERSIONS => '3', TTL => '-1', COMPRESSION => 'NONE'}]}

1 row(s) in 0.0130 seconds

4, 加入一行數據,行名稱為 Tom 列族grad的列名為”” 值位1

hbase(main):005:0> put 'scores', 'Tom', 'grade:', '1'

0 row(s) in 0.0070 seconds

5,給Tom這一行的數據的列族添加一列?

hbase(main):006:0> put 'scores', 'Tom', 'course:math', '87'

0 row(s) in 0.0040 seconds

6,給Tom這一行的數據的列族添加一列?

hbase(main):007:0> put 'scores', 'Tom', 'course:art', '97'

0 row(s) in 0.0030 seconds

7, 加入一行數據,行名稱為 Jerry 列族grad的列名為”” 值位2

hbase(main):008:0> put 'scores', 'Jerry', 'grade:', '2'

0 row(s) in 0.0040 seconds

8,給Jerry這一行的數據的列族添加一列?

hbase(main):009:0> put 'scores', 'Jerry', 'course:math', '100'

0 row(s) in 0.0030 seconds

9,給Jerry這一行的數據的列族添加一列?

hbase(main):010:0> put 'scores', 'Jerry', 'course:art', '80'

0 row(s) in 0.0050 seconds

10,查看scores表中Tom的相關數據

hbase(main):011:0> get 'scores', 'Tom'

COLUMN? ?? ?? ?? ?? ?? ?? ???CELL

course:art? ?? ?? ?? ?? ?? ?timestamp=1224726394286, value=97

course:math? ?? ?? ?? ?? ???timestamp=1224726377027, value=87

grade:? ?? ?? ?? ?? ?? ?? ? timestamp=1224726360727, value=1

3 row(s) in 0.0070 seconds

11,查看scores表中所有數據

hbase(main):012:0> scan 'scores'

ROW? ?? ?? ?? ?? ?? ?? ?? ???COLUMN+CELL

Tom? ?? ?? ?? ?? ?? ?? ?? ? column=course:art, timestamp=1224726394286, value=97

Tom? ?? ?? ?? ?? ?? ?? ?? ? column=course:math, timestamp=1224726377027, value=87

Tom? ?? ?? ?? ?? ?? ?? ?? ? column=grade:, timestamp=1224726360727, value=1

Jerry? ?? ?? ?? ?? ?? ?? ?? ?column=course:art, timestamp=1224726424967, value=80

Jerry? ?? ?? ?? ?? ?? ?? ?? ?column=course:math, timestamp=1224726416145, value=100

Jerry? ?? ?? ?? ?? ?? ?? ?? ?column=grade:, timestamp=1224726404965, value=2

6 row(s) in 0.0410 seconds

12,查看scores表中所有數據courses列族的所有數據

hbase(main):013:0> scan 'scores', ['course:']

ROW? ?? ?? ?? ?? ?? ?? ?? ???COLUMN+CELL

Tom? ?? ?? ?? ?? ?? ?? ?? ? column=course:art, timestamp=1224726394286, value=97

Tom? ?? ?? ?? ?? ?? ?? ?? ? column=course:math, timestamp=1224726377027, value=87

Jerry? ?? ?? ?? ?? ?? ?? ?? ?column=course:art, timestamp=1224726424967, value=80

Jerry? ?? ?? ?? ?? ?? ?? ?? ?column=course:math, timestamp=1224726416145, value=100

4 row(s) in 0.0200 seconds

? ? ? ? 上面就是HBase的基本shell操作的一個例子,可以看出,hbase的shell還是比較簡單易用的,從中也可以看出HBase shell缺少很多傳統sql中的一些類似于like等相關操作,當然,HBase作為BigTable的一個開源實現,而BigTable是作為 google業務的支持模型,很多sql語句中的一些東西可能還真的不需要.

? ? ? ? 當然,通過 程序我們也可以對HBase進行相關的操作.下面的程序就完成了上面shell操作的內容:

import?java.io.IOException;

import?java.io.ByteArrayOutputStream;

import?java.io.DataOutputStream;

import?java.io.ByteArrayInputStream;

import?java.io.DataInputStream;

import?java.util.Map;

import?org.apache.hadoop.io.Writable;

import?org.apache.hadoop.io.IntWritable;

import?org.apache.hadoop.hbase.HBaseConfiguration;

import?org.apache.hadoop.hbase.HTableDescriptor;

import?org.apache.hadoop.hbase.HColumnDescriptor;

import?org.apache.hadoop.hbase.client.HBaseAdmin;

import?org.apache.hadoop.hbase.client.HTable;

import?org.apache.hadoop.hbase.io.BatchUpdate;

import?org.apache.hadoop.hbase.io.RowResult;

import?org.apache.hadoop.hbase.io.Cell;

import?org.apache.hadoop.hbase.util.Writables;



public?class?HBaseBasic?{



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

????????HBaseConfiguration?config?=?new?HBaseConfiguration();

????????HBaseAdmin admin?=?new?HBaseAdmin(config);



????????if?(admin.tableExists("scores"))?{

????????????System.out.println("drop table");

????????????admin.disableTable("scores");

????????????admin.deleteTable("scores");

????????}



????????System.out.println("create table");

????????HTableDescriptor tableDescripter?=?new?HTableDescriptor("scores".getBytes());

????????tableDescripter.addFamily(new?HColumnDescriptor("grade:"));

????????tableDescripter.addFamily(new?HColumnDescriptor("course:"));

????????admin.createTable(tableDescripter);



????????HTable?table?=?new?HTable(config,?"scores");



????????System.out.println("add Tom's data");

????????BatchUpdate tomUpdate?=?new?BatchUpdate("Tom");

????????tomUpdate.put("grade:",?Writables.getBytes(new?IntWritable(1)));

????????tomUpdate.put("course:math",?Writables.getBytes(new?IntWritable(87)));

????????tomUpdate.put("course:art",?Writables.getBytes(new?IntWritable(97)));

????????table.commit(tomUpdate);



????????System.out.println("add Jerry's data");

????????BatchUpdate jerryUpdate?=?new?BatchUpdate("Jerry");

????????jerryUpdate.put("grade:",?Writables.getBytes(new?IntWritable(2)));

????????jerryUpdate.put("course:math",?Writables.getBytes(new?IntWritable(100)));

????????jerryUpdate.put("course:art",?Writables.getBytes(new?IntWritable(80)));

????????table.commit(jerryUpdate);



????????for?(RowResult row?:?table.getScanner(new?String[]?{?"course:"?}))?{

????????????System.out.format("ROW\t%s\n",?new?String(row.getRow()));

????????????for?(Map.Entry<byte[],?Cell>?entry?:?row.entrySet())?{

????????????????String?column?=?new?String(entry.getKey());

????????????????Cell cell?=?entry.getValue();

????????????????IntWritable?value?=?new?IntWritable();

????????????????Writables.copyWritable(cell.getValue(),?value);

????????????????System.out.format(" COLUMN\t%s\t%d\n",?column,?value.get());

????????????}

????????}

????}

}

? ? ? ? 輸出如下:

drop table

09/07/11 08:51:59 INFO client.HBaseAdmin: Disabled scores

09/07/11 08:51:59 INFO client.HBaseAdmin: Deleted scores

create table

add Tom's data

add Jerry's data

ROW? ???Tom

??COLUMN? ?? ???course:art? ?? ?97

??COLUMN? ?? ???course:math? ???87

ROW? ???Jerry

??COLUMN? ?? ???course:art? ?? ?80

??COLUMN? ?? ???course:math? ???100

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