How do I update table data in Hive?

How do I update table data in Hive?

Update records in a partitioned Hive table :

1. The main table is assumed to be partitioned by some key.
2. Load the incremental data (the data to be updated) to a staging table partitioned with the same keys as the main table.
3. Join the two tables (main & staging tables) using a LEFT OUTER JOIN operation as below:

How do I change column values in Hive?

Use nvl() function in Hive to replace all NULL values of a column with a default value, In this article, I will explain with an example. Replace all NULL values with -1 or 0 or any number for the integer column. Replace all NULL values with empty space for string types. Replace with any value based on your need.

How manually insert data in Hive table?

Hive – Load Data Into Table

1. Step 1: Start all your Hadoop Daemon start-dfs.sh # this will start namenode, datanode and secondary namenode start-yarn.sh # this will start node manager and resource manager jps # To check running daemons.
2. Step 2: Launch hive from terminal hive.
3. Syntax:
4. Example:
5. Command:
6. INSERT Query:

Which version of Hive supports update?

Since Hive Version 0.14, Hive supports ACID transactions like delete and update records/rows on Table with similar syntax as traditional SQL queries. You need to enable Hive ACID support and create a transactional table.

Can we update Hive external table?

2 Answers. There are two types of tables in Hive basically. One is Managed table managed by hive warehouse whenever you create a table data will be copied to internal warehouse. You can not have latest data in the query output .

How do I update the partition table in hive?

Update Hive Partition You can use Hive ALTER TABLE command to change the HDFS directory location or add new directory. Alter command will change the partition directory. ALTER TABLE some_table PARTITION(year = 2012) SET LOCATION ‘hdfs://user/user1/some_table/2012’;

Does Hive support delete and update?

Since Hive Version 0.14, Hive supports ACID transactions like delete and update records/rows on Table with similar syntax as traditional SQL queries. On a table with transactional property, hive supports ACID transactions like Update and Delete operations.

How do I add data to an existing table in Hive?

You can insert new data into table by two ways.

1. Load the data of a file into table using load command. LOAD DATA [LOCAL] INPATH ‘filepath’ [OVERWRITE] INTO TABLE tablename.
2. You can insert new data into table by using select query. INSERT INTO table tablename1 select columnlist FROM secondtable;

What does MSCK repair table do?

MSCK REPAIR TABLE recovers all the partitions in the directory of a table and updates the Hive metastore. When creating a table using PARTITIONED BY clause, partitions are generated and registered in the Hive metastore. User needs to run MSCK REPAIR TABLE to register the partitions.

How do you update an external table?

Updating external tables in Oracle

1. Define a view on the external table.
2. On this view, define INSTEAD OF triggers for insert, update and delete.
3. Write PL/SQL code in these triggers to perform the required processing.

Can we update partition column in Hive?

Hive ALTER TABLE command is used to update or drop a partition from a Hive Metastore and HDFS location (managed table). You can also manually update or drop a Hive partition directly on HDFS using Hadoop commands, if you do so you need to run the MSCK command to synch up HDFS files with Hive Metastore.