今天繼續學習 HBase 命令行操作，詳細操作如下
四、DML 操作語言
DML 是數據操作語言，用戶可以通過這些語言實現對數據的基本操作，包括數據的增刪改查
HBase DML 命令有 append、 count、 delete、 deleteall、 get、 get_counter、 get_splits、 incr、 put、 scan、 truncate、 truncate_preserve 等
1、HBase 表中添加數據
put 語法如下：
hbase> put 'ns1:t1', 'r1', 'c1', 'value'
hbase> put 't1', 'r1', 'c1', 'value'
hbase> put 't1', 'r1', 'c1', 'value', ts1
hbase> put 't1', 'r1', 'c1', 'value', {ATTRIBUTES=>{'mykey'=>'myvalue'}}
hbase> put 't1', 'r1', 'c1', 'value', ts1, {ATTRIBUTES=>{'mykey'=>'myvalue'}}
hbase> put 't1', 'r1', 'c1', 'value', ts1, {VISIBILITY=>'PRIVATE|SECRET'}
實例：
hbase(main):020:0> describe 'test'
Table test is ENABLED
test
COLUMN FAMILIES DESCRIPTION
{NAME => 'info', BLOOMFILTER => 'ROW', VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESSION => 'NONE', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE
=> '65536', REPLICATION_SCOPE => '0'}
1 row(s) in 0.0260 seconds
# 向表 test 中放入兩條數據
hbase(main):017:0* put 'test','001','info','luo'
put 'test','002','info','luo_ff'
0 row(s) in 0.0640 seconds
hbase(main):022:0> put 'test','002','info','luo_ff'
0 row(s) in 0.0090 seconds
2、統計表中數據條數
hbase(main):023:0> count 'test'
2 row(s) in 0.0040 seconds
=> 2
3、查看錶中數據
HBase 中數據的瀏覽有兩種方式，一種是全表掃描，一種是指定獲取到一條數據，全表掃描 用 scan 命令，指定獲取某條數據 用 get 命令，具體使用如下：
3.1 scan 全表掃描
命令語法如下：
Some examples:
hbase> scan 'hbase:meta'
hbase> scan 'hbase:meta', {COLUMNS => 'info:regioninfo'}
hbase> scan 'ns1:t1', {COLUMNS => ['c1', 'c2'], LIMIT => 10, STARTROW => 'xyz'}
hbase> scan 't1', {COLUMNS => ['c1', 'c2'], LIMIT => 10, STARTROW => 'xyz'}
hbase> scan 't1', {COLUMNS => 'c1', TIMERANGE => [1303668804, 1303668904]}
hbase> scan 't1', {REVERSED => true}
hbase> scan 't1', {ALL_METRICS => true}
hbase> scan 't1', {METRICS => ['RPC_RETRIES', 'ROWS_FILTERED']}
hbase> scan 't1', {ROWPREFIXFILTER => 'row2', FILTER => "
(QualifierFilter (>=, 'binary:xyz')) AND (TimestampsFilter ( 123, 456))"}
hbase> scan 't1', {FILTER =>
org.apache.hadoop.hbase.filter.ColumnPaginationFilter.new(1, 0)}
hbase> scan 't1', {CONSISTENCY => 'TIMELINE'}
For setting the Operation Attributes
hbase> scan 't1', { COLUMNS => ['c1', 'c2'], ATTRIBUTES => {'mykey' => 'myvalue'}}
hbase> scan 't1', { COLUMNS => ['c1', 'c2'], AUTHORIZATIONS => ['PRIVATE','SECRET']}
For experts, there is an additional option -- CACHE_BLOCKS -- which
switches block caching for the scanner on (true) or off (false). By
default it is enabled. Examples:
hbase> scan 't1', {COLUMNS => ['c1', 'c2'], CACHE_BLOCKS => false}
Also for experts, there is an advanced option -- RAW -- which instructs the
scanner to return all cells (including delete markers and uncollected deleted
cells). This option cannot be combined with requesting specific COLUMNS.
Disabled by default. Example:
hbase> scan 't1', {RAW => true, VERSIONS => 10}
實例：
hbase(main):033:0> scan 'test'
ROW COLUMN+CELL
001 column=info:, timestamp=1574130792106, value=luo
002 column=info:, timestamp=1574131392911, value=luo_ff
2 row(s) in 0.0120 seconds
3.2 HBase 單條數據查詢（get）
get 查詢單條數據語法如下：
hbase> t.get 'r1'
hbase> t.get 'r1', {TIMERANGE => [ts1, ts2]}
hbase> t.get 'r1', {COLUMN => 'c1'}
hbase> t.get 'r1', {COLUMN => ['c1', 'c2', 'c3']}
hbase> t.get 'r1', {COLUMN => 'c1', TIMESTAMP => ts1}
hbase> t.get 'r1', {COLUMN => 'c1', TIMERANGE => [ts1, ts2], VERSIONS => 4}
hbase> t.get 'r1', {COLUMN => 'c1', TIMESTAMP => ts1, VERSIONS => 4}
hbase> t.get 'r1', {FILTER => "ValueFilter(=, 'binary:abc')"}
hbase> t.get 'r1', 'c1'
hbase> t.get 'r1', 'c1', 'c2'
hbase> t.get 'r1', ['c1', 'c2']
hbase> t.get 'r1', {CONSISTENCY => 'TIMELINE'}
hbase> t.get 'r1', {CONSISTENCY => 'TIMELINE', REGION_REPLICA_ID => 1}
實例：
hbase(main):003:0> get 'test','001'
COLUMN CELL
info: timestamp=1574146101757, value=luo
1 row(s) in 0.0230 seconds
4、在某一列的值後面追加
追加值使用 append 命令，命令語法如下:
hbase> append 't1', 'r1', 'c1', 'value', ATTRIBUTES=>{'mykey'=>'myvalue'}
hbase> append 't1', 'r1', 'c1', 'value', {VISIBILITY=>'PRIVATE|SECRET'
同樣的命令也可以在表引用上運行，語法如下：
The same commands also can be run on a table reference. Suppose you had a reference
t to table 't1', the corresponding command would be:
hbase> t.append 'r1', 'c1', 'value', ATTRIBUTES=>{'mykey'=>'myvalue'}
hbase> t.append 'r1', 'c1', 'value', {VISIBILITY=>'PRIVATE|SECRET'}
實例：
hbase(main):012:0> append 'test','001','info:luo','luoluo'
CURRENT VALUE = luoluo
0 row(s) in 0.0280 seconds
hbase(main):013:0> scan 'test'
ROW COLUMN+CELL
001 column=info:, timestamp=1574146101757, value=luo
001 column=info:luo, timestamp=1574154430334, value=luoluo
002 column=info:, timestamp=1574146107500, value=luo_ff
5、刪除數據
HBase 刪除數據語法如下：
hbase> delete 'ns1:t1', 'r1', 'c1', ts1
hbase> delete 't1', 'r1', 'c1', ts1
hbase> delete 't1', 'r1', 'c1', ts1, {VISIBILITY=>'PRIVATE|SECRET'}
hbase> t.delete 'r1', 'c1', ts1
hbase> t.delete 'r1', 'c1', ts1, {VISIBILITY=>'PRIVATE|SECRET'}
實例：
# 刪除表 test 中的數據
hbase(main):018:0* delete "test","001","info:luo",1574130792106
0 row(s) in 0.0070 seconds
6、刪除行或者整個列族
使用 deleteall 命令刪除行或者整個列族，使用命令如下：
hbase> deleteall 'ns1:t1', 'r1'
hbase> deleteall 't1', 'r1'
hbase> deleteall 't1', 'r1', 'c1'
hbase> deleteall 't1', 'r1', 'c1', ts1
hbase> deleteall 't1', 'r1', 'c1', ts1, {VISIBILITY=>'PRIVATE|SECRET'}
The same commands also can be run on a table reference. Suppose you had a reference
t to table 't1', the corresponding command would be:
hbase> t.deleteall 'r1'
hbase> t.deleteall 'r1', 'c1'
hbase> t.deleteall 'r1', 'c1', ts1
hbase> t.deleteall 'r1', 'c1', ts1, {VISIBILITY=>'PRIVATE|SECRET'}
實例：
hbase(main):017:0* deleteall 'test','001'
0 row(s) in 0.0120 seconds
hbase(main):018:0> scan 'test'
ROW COLUMN+CELL
002 column=info:, timestamp=1574146107500, value=luo_ff
1 row(s) in 0.0110 seconds
7、清空表數據
清空表數據有兩個命令，一個是truncate，另一個是truncate_preserve，truncate_preserve 只清空數據，不刪除region的劃分規則
實例：
hbase(main):025:0> truncate 'test'
Truncating 'test' table (it may take a while):
- Disabling table...
- Truncating table...
0 row(s) in 3.3770 seconds
hbase(main):029:0> truncate_preserve 'test1'
Truncating 'test1' table (it may take a while):
- Disabling table...
- Truncating table...
0 row(s) in 1.1490 seconds
通過上述實例可以看出，清空表數據的步驟首先先禁用此表，然後在清空表中數據
五、其他操作命令
HBase 除了第 4 天學習的 和以上基礎命令外，還有其他一些運用更廣泛的命令，這些命令我將在後面的時間瞭解透徹後作詳細的介紹，一起靜待，除了基礎命令外，HBase 其他命令如下：
Group name: tools
Commands: assign, balance_switch, balancer, balancer_enabled, catalogjanitor_enabled, catalogjanitor_run, catalogjanitor_switch, cleaner_chore_enabled, cleaner_chore_run, cleaner_chore_switch, clear_deadservers, close_region, compact, compact_rs, compaction_state, flush, is_in_maintenance_mode, list_deadservers, major_compact, merge_region, move, normalize, normalizer_enabled, normalizer_switch, split, splitormerge_enabled, splitormerge_switch, trace, unassign, wal_roll, zk_dump
Group name: replication
Commands: add_peer, append_peer_tableCFs, disable_peer, disable_table_replication, enable_peer, enable_table_replication, get_peer_config, list_peer_configs, list_peers, list_replicated_tables, remove_peer, remove_peer_tableCFs, set_peer_bandwidth, set_peer_tableCFs, show_peer_tableCFs, update_peer_config
Group name: snapshots
Commands: clone_snapshot, delete_all_snapshot, delete_snapshot, delete_table_snapshots, list_snapshots, list_table_snapshots, restore_snapshot, snapshot
Group name: configuration
Commands: update_all_config, update_config
Group name: quotas
Commands: list_quotas, set_quota
Group name: security
Commands: grant, list_security_capabilities, revoke, user_permission
Group name: procedures
Commands: abort_procedure, list_procedures
Group name: visibility labels
Commands: add_labels, clear_auths, get_auths, list_labels, set_auths, set_visibility
Group name: rsgroup
Commands: add_rsgroup, balance_rsgroup, get_rsgroup, get_server_rsgroup, get_table_rsgroup, list_rsgroups, move_servers_rsgroup, move_servers_tables_rsgroup, move_tables_rsgroup, remove_rsgroup, remove_servers_rsgroup
總結，今天的文章是對 HBase 基礎命令的瞭解與運用，除了基礎命令以外，HBase 還有其他更有意思的命令，就如以上第二點的命令，這些命令我將在後面的作詳細介紹。