这里分类和汇总了欣宸的全部原创(含配套源码):https://github.com/zq2599/blog_demos
create database if not exists test
comment 'this is a database for test';
hive> show databases like 't*';
OK
test
test001
Time taken: 0.016 seconds, Fetched: 2 row(s)
hive> describe database test;
OK
test this is a database for test hdfs://node0:8020/user/hive/warehouse/test.db hadoop USER
Time taken: 0.035 seconds, Fetched: 1 row(s)
hive> drop database if exists test;
OK
Time taken: 0.193 seconds
以上就是常用的库相关操作,接下来实践表相关操作;
create table t6(id int, name string)
row format delimited
fields terminated by ',';
insert into t6 values (101, 'a101');
[hadoop@node0 bin]$ ./hadoop fs -ls /user/hive/warehouse/t6
Found 1 items
-rwxr-xr-x 3 hadoop supergroup 9 2020-10-31 11:14 /user/hive/warehouse/t6/000000_0
[hadoop@node0 bin]$ ./hadoop fs -cat /user/hive/warehouse/t6/000000_0
101 a101
[hadoop@node0 bin]$ ./hadoop fs -ls /user/hive/warehouse/
Found 5 items
drwxr-xr-x - hadoop supergroup 0 2020-10-27 20:42 /user/hive/warehouse/t1
drwxr-xr-x - hadoop supergroup 0 2020-10-29 00:13 /user/hive/warehouse/t2
drwxr-xr-x - hadoop supergroup 0 2020-10-29 00:14 /user/hive/warehouse/t3
drwxr-xr-x - hadoop supergroup 0 2020-10-29 13:04 /user/hive/warehouse/t4
drwxr-xr-x - hadoop supergroup 0 2020-10-29 16:47 /user/hive/warehouse/t5
create external table t7(id int, name string)
row format delimited
fields terminated by ','
location '/data/external_t7';
[hadoop@node0 bin]$ ./hadoop fs -ls /data/
Found 1 items
drwxr-xr-x - hadoop supergroup 0 2020-10-31 12:02 /data/external_t7
insert into t7 values (107, 'a107');
[hadoop@node0 bin]$ ./hadoop fs -ls /data/external_t7
Found 1 items
-rwxr-xr-x 3 hadoop supergroup 9 2020-10-31 12:06 /data/external_t7/000000_0
[hadoop@node0 bin]$ ./hadoop fs -cat /data/external_t7/000000_0
107,a107
create external table t8(id_t8 int, name_t8 string)
row format delimited
fields terminated by ','
location '/data/external_t7';
hive> select * from t8;
OK
107 a107
Time taken: 0.068 seconds, Fetched: 1 row(s)
hive> select * from t7;
OK
107 a107
Time taken: 0.074 seconds, Fetched: 1 row(s)
hive> drop table t7;
OK
Time taken: 1.053 seconds
hive> select * from t8;
OK
107 a107
Time taken: 0.073 seconds, Fetched: 1 row(s)
[hadoop@node0 bin]$ ./hadoop fs -cat /data/external_t7/000000_0
107,a107
create table t8(id int, name string)
row format delimited
fields terminated by ',';
alter table t8 rename to t8_1;
hive> alter table t8 rename to t8_1;
OK
Time taken: 0.473 seconds
hive> show tables;
OK
alltype
t1
t2
t3
t4
t5
t6
t8_1
values__tmp__table__1
values__tmp__table__2
Time taken: 0.029 seconds, Fetched: 10 row(s)
alter table t8_1 add columns(remark string);
查看表结构,可见已经生效:
hive> desc t8_1;
OK
id int
name string
remark string
Time taken: 0.217 seconds, Fetched: 3 row(s)
至此,咱们对内部表和外部表已经有了基本了解,接下来的文章学习另一种常见的表类:分区表;
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微信搜索「程序员欣宸」,我是欣宸,期待与您一同畅游Java世界...
原创声明:本文系作者授权腾讯云开发者社区发表,未经许可,不得转载。
如有侵权,请联系 cloudcommunity@tencent.com 删除。
原创声明:本文系作者授权腾讯云开发者社区发表,未经许可,不得转载。
如有侵权,请联系 cloudcommunity@tencent.com 删除。