You have an Azure subscription that contains a Delta Lake solution. The solution contains a table named employees. You need to view the contents of the employees table from 24 hours ago. You must minimize the time it takes to retrieve the data. What should you do?

Category : Microsoft Azure Data Engineering | Sub Category : Practice Assessment for Exam DP-203 - Data Engineering on Microsoft Azure | By Prasad Bonam Last updated: 2023-09-10 00:23:39 Viewed : 310

o view the contents of the "employees" table from 24 hours ago in an Azure Delta Lake solution, you can use the Delta Lake time travel feature. Delta Lake provides versioning for tables, allowing you to access the data as it existed at a specific point in time. Here is how you can do it:

1. 
   

   1. Connect to your Delta Lake solution: Use the appropriate tool or SDK to connect to your Azure Delta Lake solution. Common options include Azure Databricks, Azure Synapse Analytics, or Azure Data Lake Storage.

   2. Use the AS OF clause: In Delta Lake, you can use the AS OF clause to specify a timestamp or version to query the data as it existed at that time. In your case, you want to view the data from 24 hours ago.

   Here is an example SQL query to achieve this:

   sqlCopy code
   -- Connect to your Delta Lake solution first
   
   -- Query the "employees" table as it existed 24 hours ago
   SELECT *
   FROM employees AS OF TIMESTAMP (NOW() - INTERVAL 24 HOURS);
   

   In this query, the AS OF TIMESTAMP clause is used to specify a timestamp 24 hours ago. Adjust the table name ("employees") and connection details as needed for your Azure Delta Lake solution.

   3. Execute the query: Run the SQL query using the tool or SDK you have chosen to connect to your Delta Lake solution.

   This query will retrieve the contents of the "employees" table as they existed 24 hours ago, utilizing the Delta Lake time travel feature. Make sure your environment is properly set up to work with Delta Lake, and you have the necessary permissions to access the table and query historical data.