HBase 常用Shell命令(二)

1. hbase(main):079:0> create 'scores',{NAME=>'course',VERSIONS=>2}
   
2. 0 row(s) in 0.9590 seconds
3.  hbase(main):080:0> put 'scores','Tom','course:math','97'
4. 0 row(s) in 0.0100 seconds

 

1. hbase(main):081:0> scan 'scores'
   
2. ROW COLUMN+CELL
3. Tom column=course:math, timestamp=1394097631387, value=97
4. 1 row(s) in 0.0190 seconds
6. hbase(main):082:0> put 'scores','Tom','course:math','100'
7. 0 row(s) in 0.0080 seconds
9. hbase(main):026:0> scan 'scores'
10. ROW COLUMN+CELL
11. Tom column=course:math, timestamp=1394097651029, value=100
12. 1 row(s) in 0.0110 seconds
14. hbase(main):027:0> scan 'scores',{TIMERANGE=>[1394097631387,1394097651029]}
15. ROW COLUMN+CELL
16. Tom column=course:math, timestamp=1394097631387, value=97
17. 1 row(s) in 0.0210 seconds
19. hbase(main):028:0> scan 'scores',{TIMERANGE=>[1394097631387,1394097651030]}
20. ROW COLUMN+CELL
21. Tom column=course:math, timestamp=1394097651029, value=100
22. 1 row(s) in 0.0100 seconds

从上面可以看到，HBASE默认scan出来的结果是最后一条时间戳的记录，那么如何把这两条都scan出来呢，
这时候可以加入VERSIONS这个约束条件：

1. hbase(main):032:0> scan 'scores',{VERSIONS=>2}
   
2. ROW COLUMN+CELL
3. Tom column=course:math, timestamp=1394097651029, value=100
4. Tom column=course:math, timestamp=1394097631387, value=97
5. 1 row(s) in 0.0130 seconds

 上面的命令，已经把这条记录都scan出来了。

再看下面的例子：

1. scan 'scores',{TIMERANGE=>[1394097631386,1394097651029],VERSIONS=>2}
   
2. ROW COLUMN+CELL
3.  Tom column=course:math, timestamp=1394097631387, value=97
4. 1 row(s) in 0.0130 seconds

 从上面的结果只scan出一条记录。可知，TIMERANGE表示的是”>=开始时间 and <结束时间“的。再看：

1. hbase(main):003:0> scan 'scores',{TIMERANGE=>[1394097631386,1394097651030],VERSIONS=>2}
   
2. ROW COLUMN+CELL
3.  Tom column=course:math, timestamp=1394097651029, value=100
4.  Tom column=course:math, timestamp=1394097631387, value=97
5. 1 row(s) in 0.0100 seconds

 OK，这样就明白了。
 不过上面的加了VERSIONS=>2，就可以查到历史的数据了，但是必须再创建表的时候加上VERSIONS,否则无效,看下面的例子：

1. hbase(main):082:0> create 'member','address','info'
   
2. 0 row(s) in 0.4140 seconds
4. => Hbase::Table - member

1. hbase(main):093:0> put 'member','wanglei','info:age','24'
   
2. 0 row(s) in 0.0730 seconds

1. hbase(main):093:1>get 'member','wanglei',{COLUMN=>'info:age'}
2. COLUMN         CELL
3.  info:age timestamp=1394438746187, value=24
4. hbase(main):093:7> put 'member','wanglei','info:age','99'
5. 0 row(s) in 0.0730 seconds
6. hbase(main):093:18> get 'member','wanglei',{COLUMN=>'info:age'}
7. COLUMN                             CELL
8. info:age                          timestamp=1394439539837, value=100 
   

 

     

 

1. hbase(main):022:0> get 'member','wanglei',{COLUMN=>'info:age',TIMERANGE=>[1394438746187,1394439539838],VERSIONS=>2}
   
2. COLUMN CELL
3.  info:age imestamp=1394439539837, value=100
4. 1 row(s) in 0.0050 seconds

 可以看到，虽然加了VERSIONS，但get的结果是1条；这就是因为建表时默认的VERSION是1.
修改VERSIONS：

1. hbase(main):029:0> alter 'member',{NAME=>'info','VERSIONS'=>2}
   
2. Updating all regions with the new schema...
3. 0/1 regions updated.
4. 1/1 regions updated.
5. Done.
6. 0 row(s) in 2.1680 seconds

 

 

1. hbase(main):046:0> put 'member','wanglei','info:age','101'
   
2. 0 row(s) in 0.0590 seconds
4. hbase(main):047:0> get 'member','wanglei',{COLUMN=>'info:age'}
5. COLUMN CELL
6.  info:age timestamp=1394441161595, value=101
7. 1 row(s) in 0.0120 seconds

   那么现在就可以把倆条记录get出来了,如下：
  

1. hbase(main):049:0> get 'member','wanglei',{COLUMN=>'info:age',TIMERANGE=>[1394439539837,1394441161596],VERSIONS=>2}
   
2. COLUMN CELL
3.  info:age timestamp=1394441161595, value=101
4.  info:age timestamp=1394439539837, value=100
5. 2 row(s) in 0.0080 seconds