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魯春利的工作筆記，誰說程序員不能有文藝范？
在hive中創建mywork數據庫，以后的測試在該數據庫中進行，避免每次都使用default數據庫。
hive> create database mywork; OK Time taken: 0.487 seconds hive> show databases; OK default mywork Time taken: 0.614 seconds, Fetched: 2 row(s) hive> hive> use mywork; OK Time taken: 0.064 seconds hive> create table student(id int, name string); OK Time taken: 0.519 seconds hive>
查看Hive在HDFS上的存儲
[hadoop@dnode1 ~]$ hdfs dfs -ls -R /user/hive drwxrw-rw- - hadoop hadoop 0 2015-12-08 21:37 /user/hive/warehouse drwxrw-rw- - hadoop hadoop 0 2015-12-08 21:36 /user/hive/warehouse/mywork.db drwxrw-rw- - hadoop hadoop 0 2015-12-08 21:36 /user/hive/warehouse/mywork.db/student [hadoop@dnode1 ~]$
Hive支持的數據類型如下:
原生類型:
TINYINT 1字節 SMALLINT 2字節 INT 4字節 BIGINT 8字節 BOOLEAN true/false FLOAT 4字節 DOUBLE 8字節 STRING 字符串 BINARY (Hive 0.8.0以上才可用) TIMESTAMP (Hive 0.8.0以上才可用)
復合類型:
arrays: ARRAY<data_type> 有序字段，類型必須相同 maps: MAP<primitive_type, data_type> 無序的鍵/值對 structs: STRUCT<col_name : data_type [COMMENT col_comment], ...> 一組命名的字段 union: UNIONTYPE<data_type, data_type, ...>
說明：ARRAY數據類型通過下標來獲取值，如arrays[0]，MAP通過["指定域名稱"]訪問， STRUCT類型通過點方式訪問（如structs.col_name)。
建表示例：
hive> create table employee ( > eno int comment 'the no of employee', > ename string comment 'name of employee', > salary float comment 'salary of employee', > subordinates array<string> comment 'employees managed by current employee', > deductions map<string, float> comment 'deductions', > address struct<province : string, city : string, street : string, zip : int> comment 'address' > ) comment 'This is table of employee info'; OK Time taken: 0.33 seconds hive>
在Hive中各列之間，以及復合類型內部使用了不同的分隔符來指定，每行數據對應一條記錄。
在${HIVE_HOME}/data目錄下創建文件data_default.txt文件，采用默認分隔符，內容為：
Hive默認的字段分隔符為ascii碼的控制符\001，建表的時候用fields terminated by '\001'。造數據在vi 打開文件里面，用ctrl+v然后再ctrl+a可以輸入這個控制符\001（即^A）。按順序，\002的輸入方式為ctrl+v,ctrl+b。以此類推。
說明：
1000 員工編號 zhangsan 員工姓名 5000.0 員工工資 lisi^Bwangwu 下屬員工 ptax^C200^Bpension^C200 工資扣除金額（如稅收等） shandong^Bheze^Bdingtao^B274106 家庭住址（struct結構只需指定值即可）
加載數據
hive> load data local inpath 'data/data_default.txt' into table employee;
Loading data to table mywork.employee
Table mywork.employee stats: [numFiles=1, numRows=0, totalSize=83, rawDataSize=0]
OK
Time taken: 0.426 seconds
hive> select * from employee;
OK
1000 zhangsan 5000.0 ["lisi","wangwu"] {"ptax":200.0,"pension":200.0} {"province":"shandong","city":"heze","street":"dingtao","zip":274106}
Time taken: 0.114 seconds, Fetched: 1 row(s)
hive>
# 對于復合類型數據查詢方式如下
hive> select eno, ename, salary, subordinates[0], deductions['ptax'], address.province from employee;
OK
1000 zhangsan 5000.0 lisi 200.0 shandong
Time taken: 0.129 seconds, Fetched: 1 row(s)
hive>查看HDFS數據結構
[hadoop@dnode1 ~]$ hdfs dfs -ls -R /user/hive/warehouse/ drwxrw-rw- - hadoop hadoop 0 2015-12-09 00:00 /user/hive/warehouse/mywork.db drwxrw-rw- - hadoop hadoop 0 2015-12-09 00:00 /user/hive/warehouse/mywork.db/employee -rwxrw-rw- 2 hadoop hadoop 83 2015-12-09 00:00 /user/hive/warehouse/mywork.db/employee/data_default.txt drwxrw-rw- - hadoop hadoop 0 2015-12-08 23:03 /user/hive/warehouse/mywork.db/student [hadoop@dnode1 ~]$ hdfs dfs -text /user/hive/warehouse/mywork.db/employee/data_default.txt 1000zhangsan5000.0lisiwangwuptax200pension200shandonghezedingtao274106 [hadoop@dnode1 ~]$
自定義分隔符：
hive> create table employee_02 (
> eno int comment 'the no of employee',
> ename string comment 'name of employee',
> salary float comment 'salary of employee',
> subordinates array<string> comment 'employees managed by current employee',
> deductions map<string, float> comment 'deductions',
> address struct<province : string, city : string, street : string, zip : int> comment 'address'
> ) comment 'This is table of employee info'
> row format delimited fields terminated by '\t'
> collection items terminated by ','
> map keys terminated by ':'
> lines terminated by '\n';
OK
Time taken: 0.228 seconds
hive> load data local inpath 'data/data_employee02.txt' into table employee_02;
Loading data to table mywork.employee_02
Table mywork.employee_02 stats: [numFiles=1, totalSize=99]
OK
Time taken: 0.371 seconds
hive> select * from employee_02;
OK
1000 'zhangsan' 5000.0 ["'lisi'","'wangwu'"] {"'ptax'":200.0,"'pension'":200.0} {"province":"'shandong'","city":"'heze'","street":"'dingtao'","zip":274106}
Time taken: 0.101 seconds, Fetched: 1 row(s)
hive>data/employee02.txt文件內容為
[hadoop@nnode data]$ pwd /usr/local/hive1.2.0/data [hadoop@nnode data]$ cat data_employee02.txt 1000 'zhangsan' 5000.0 'lisi','wangwu' 'ptax':200,'pension':200 'shandong','heze','dingtao',274106 [hadoop@nnode data]$
說明：由于在文本文件中包含有單引號，在load到hive的表之后表示方式為屬性加雙引號，這里的單引號被認為了是屬性或值的一部分了，需要注意。
查看詳細表定義
# 建表時為默認設置 hive> describe formatted employee; OK # col_name data_type comment eno int the no of employee ename string name of employee salary float salary of employee subordinates array<string> employees managed by current employee deductions map<string,float> deductions address struct<province:string,city:string,street:string,zip:int> address # Detailed Table Information Database: mywork Owner: hadoop CreateTime: Tue Dec 08 23:10:07 CST 2015 LastAccessTime: UNKNOWN Protect Mode: None Retention: 0 Location: hdfs://cluster/user/hive/warehouse/mywork.db/employee Table Type: MANAGED_TABLE Table Parameters: COLUMN_STATS_ACCURATE true comment This is table of employee info numFiles 1 numRows 0 rawDataSize 0 totalSize 83 transient_lastDdlTime 1449590423 # Storage Information SerDe Library: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe InputFormat: org.apache.hadoop.mapred.TextInputFormat OutputFormat: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat Compressed: No Num Buckets: -1 Bucket Columns: [] Sort Columns: [] Storage Desc Params: serialization.format 1 Time taken: 0.098 seconds, Fetched: 37 row(s) # 建表時自定義了分隔符 hive> describe formatted employee_02; OK # col_name data_type comment eno int the no of employee ename string name of employee salary float salary of employee subordinates array<string> employees managed by current employee deductions map<string,float> deductions address struct<province:string,city:string,street:string,zip:int> address # Detailed Table Information Database: mywork Owner: hadoop CreateTime: Wed Dec 09 00:12:53 CST 2015 LastAccessTime: UNKNOWN Protect Mode: None Retention: 0 Location: hdfs://cluster/user/hive/warehouse/mywork.db/employee_02 Table Type: MANAGED_TABLE Table Parameters: COLUMN_STATS_ACCURATE true comment This is table of employee info numFiles 1 totalSize 99 transient_lastDdlTime 1449591260 # Storage Information SerDe Library: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe InputFormat: org.apache.hadoop.mapred.TextInputFormat OutputFormat: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat Compressed: No Num Buckets: -1 Bucket Columns: [] Sort Columns: [] Storage Desc Params: colelction.delim , field.delim \t line.delim \n mapkey.delim : serialization.format \t Time taken: 0.116 seconds, Fetched: 39 row(s) hive>
遺留問題：
hive> delete from student; FAILED: SemanticException [Error 10294]: Attempt to do update or delete using transaction manager that does not support these operations. hive>
注意事項：如果sql語句中含有tab格式的內容，則會出現如下問題
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