hive内表和外表的创建、载入数据、区别 |
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hive内表和外表的创建、载入数据、区别
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创建表
创建内表 create table customer( customerId int, firstName string, lastName STRING, birstDay timestamp ) row format delimited fields terminated by ','创建外表 CREATE EXTERNAL table salaries( gender string, age int , salary DOUBLE, zip int )row format delimited fields terminated by ',' LOCATION '/user/train/salaries/'; 载入数据 load DATA LOCAL inpath '/root/user/customer.txt' overwrite into table customer; load DATA LOCAL inpath '/root/user/salaries.txt' overwrite into table salaries;查看文本数据 [root@centos172 user]# cat /root/user/customer.txt 1,f,jack,, 2,f,luccy,, [root@centos172 user]# cat /root/user/salaries.txt male,21,10000,1 female,22,12000,2查看数据库数据 hive> desc customer; OK customerid int firstname string lastname string birstday timestamp Time taken: 0.053 seconds, Fetched: 4 row(s) hive> desc salaries; OK gender string age int salary double zip int Time taken: 0.041 seconds, Fetched: 4 row(s) hive> select * from customer; OK 1 f jack NULL 2 f luccy NULL Time taken: 0.067 seconds, Fetched: 2 row(s) hive> select * from salaries; OK male 21 10000.0 1 female 22 12000.0 2 Time taken: 0.066 seconds, Fetched: 2 row(s) hive> 区别因为我hive也是刚开始了解，所以只讲一部分 1.内表主要放在hdfs中默认的hive目录。外表指定了location 2.删除内表，重新创建一个一样的内表，数据不会装载 删除外表，重新创建一个一样的外表，数据会自动的装载 删除外表的操作如下 hive> drop table salaries; OK Time taken: 0.092 seconds hive> select * from salaries; FAILED: SemanticException [Error 10001]: Line 1:14 Table not found 'salaries' hive> show tables; OK customer Time taken: 0.035 seconds, Fetched: 1 row(s) hive> CREATE EXTERNAL table salaries( > gender string, > age int , > salary DOUBLE, > zip int > )row format delimited fields terminated by ',' LOCATION '/user/train/salaries/'; OK Time taken: 0.058 seconds hive> show tables; OK customer salaries Time taken: 0.025 seconds, Fetched: 2 row(s) hive> select * from salaries; OK male 21 10000.0 1 female 22 12000.0 2 Time taken: 0.058 seconds, Fetched: 2 row(s) hive>区别1的：
内表的默认路径
指定外表的路径如图：
我当前接触到就是： 1.把hdf文件具体为table 2.用来查询，类似sql语句处理 |
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