Data Engineering Spark SQL - Managing Tables - DDL & DML - Truncating Tables

Databases Postgres
1

Let us understand how to truncate tables.

Explanation for the video

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Key Concepts Explanation

Key Concept 1

The TRUNCATE command works only for managed tables. It deletes only the data, while the structure of the table is retained. Here is an example code snippet:

TRUNCATE TABLE orders

Key Concept 2

Creating an external table in Spark SQL. Here is an example code snippet:

CREATE EXTERNAL TABLE orders (
  order_id INT,
  order_date STRING,
  order_customer_id INT,
  order_status STRING
) ROW FORMAT DELIMITED FIELDS TERMINATED BY ','
LOCATION '/user/itversity/external/retail_db/orders'

Hands-On Tasks

  1. Execute the TRUNCATE command on a managed table in your Spark SQL environment.
  2. Create an external table in Spark SQL using the provided code snippet.

Conclusion

In this article, we have learned about truncating tables in Spark SQL. Remember that the TRUNCATE command only works for managed tables and retains the table structure while deleting data. Practice these concepts in your own Spark SQL environment and feel free to engage with the community for further learning opportunities.

Watch the video tutorial here