如何使用外部表指向单个文件 [英] How to point to a single file with external table

问题描述

我正在尝试将hdfs数据作为外部加载，但出现以下错误.

Im trying to load hdfs data as external but get the following error.

ml-100k文件夹包含具有不同数据集的多个数据集，因此我只需要加载该特定文件.

The folder ml-100k has multiple datasets with different datasets, so I just need to load that particular file.

hive> create external table movie_ratings (movie_id int, user_id int, ratings int, field_4 int) location 'hdfs://hadoop-master:8020/user/hduser/gutenberg/ml-100k/u.data'
    > ;
FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. MetaException(message:hdfs://hadoop-master:8020/user/hduser/gutenberg/ml-100k/u.data is not a directory or unable to create one)

推荐答案

您不能创建指向文件，仅指向目录的表，但是有一个功能/错误允许您将位置更改为特定位置文件.

You cannot create a table that points to a file, only to a directory, but there is a feature/bug that allows you to alter the location to a specific file.

create external table movie_ratings (movie_id int, user_id int, ratings int, field_4 int) location 'hdfs://hadoop-master:8020/user/hduser/gutenberg/ml-100k';

alter table movie_ratings set location 'hdfs://hadoop-master:8020/user/hduser/gutenberg/ml-100k/u.data';

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