How to delete and update a record in Hive

Question

I have installed Hadoop, Hive, Hive JDBC. which are running fine for me. But I still have a problem. How to delete or update a single record using Hive because delete or upd

Answer 1

Yes, rightly said. Hive does not support UPDATE option. But the following alternative could be used to achieve the result:

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:

   insert overwrite table main_table partition (c,d) select t2.a, t2.b, t2.c,t2.d from staging_table t2 left outer join main_table t1 on t1.a=t2.a;

In the above example, the main_table & the staging_table are partitioned using the (c,d) keys. The tables are joined via a LEFT OUTER JOIN and the result is used to OVERWRITE the partitions in the main_table.

A similar approach could be used in the case of un-partitioned Hive table UPDATE operations too.