Shulou(Shulou.com)06/02 Report--

Hive external table partition is how, many novices are not very clear about this, in order to help you solve this problem, the following editor will explain in detail for you, people with this need can come to learn, I hope you can gain something.

1: definition

The internal table (MANAGED TABLE) is not modified by external, and the external table (EXTERNAL TABLE) is decorated by external.

Create external table syntax:

Create external table person2 (id int, name string, hobby array, addr map) row format delimited fields terminated by', 'collection items terminated by'-'map keys terminated by': 'location' / user/person2'

2: difference

1) Internal table data is managed by hive itself, and external table data is managed by hdfs

Location of internal table data storage default / user/hive/warehouse

The location of external table data storage is specified by the user.

2) deleting internal tables directly deletes metadata and stored data

Deleting an external table only deletes the metadata, not the files on the HDFS.

3: partition table

1) define syntax

Create table p1 (id int, name string, hobby array, addr map) partitioned by (p_dt string) row format delimited fields terminated by', 'collection items terminated by'-'map keys terminated by':'

Note: partition fields cannot be duplicated with fields in the table. To create a partition table, you must create a partition when the table is defined.

Is it helpful for you to read the above content? If you want to know more about the relevant knowledge or read more related articles, please follow the industry information channel, thank you for your support.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.