This post is first created by CodingMrWang, 作者 @Zexian Wang ,please keep the original link if you want to repost it.
Hive
Apache Hive is a data warehouse software project built on top of Apache Hadoop for providing data summarization, query and analysis. Hive gives an SQL-like interface to query data stored in various databases and file systems that integrate with Hadoop.
Create:
CREATE TABLE content.post_dict (
post_id STRING COMMENT 'This is primary key',
url STRING,
mp_id BIGINT,
title STRING,
content STRING,
publish_time STRING,
update_time STRING,
) PARTITIONED BY (date STRING) ROW FORMAT SERDE 'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe' STORED AS INPUTFORMAT 'org.apache.hadoop.hive.ql.io.parquet.MapredParquetInputFormat' OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.parquet.MapredParquetOutputFormat'
It is really important to add format constraint. The default separator is ‘\u0001’ in hive, so if your content contains this separator, it will become a mess in your hive table. I suffered this before when I transfer data from abase to hive.
Delete:
DROP TABLE IF EXISTS [db.name].[table.name];
Alter:
ALTER TABLE [old_db_name.]old_table_name RENAME TO [new_db_name.]new_table_name
ALTER TABLE name ADD COLUMNS (col_spec[, col_spec ...])
ALTER TABLE name DROP [COLUMN] column_name
ALTER TABLE name CHANGE column_name col_spec
ALTER TABLE name REPLACE COLUMNS (col_spec[, col_spec ...])
ALTER TABLE name { ADD [IF NOT EXISTS] | DROP [IF EXISTS] } PARTITION (partition_spec) [PURGE]
ALTER TABLE name RECOVER PARTITIONS
