How to Restore a Table to a Previous State Using Temporal Data

Restoring a Table to a Previous State Using Temporal Data

Write a SQL query to restore a table to a previous state using temporal data.

Solution:

-- Restore the Employees table to its state as of October 1, 2023.
BEGIN TRANSACTION;

DELETE FROM Employees;

INSERT INTO Employees (EmployeeID, Name, Position, SysStartTime, SysEndTime)
SELECT EmployeeID, Name, Position, SysStartTime, SysEndTime
FROM Employees
FOR SYSTEM_TIME AS OF '2023-10-01';

COMMIT TRANSACTION;

Explanation:

• Purpose of the Query :
• The goal is to demonstrate how to restore a table to a previous state using temporal data.
• Key Components :
• FOR SYSTEM_TIME AS OF: Retrieves data valid at the specified timestamp.
• DELETE and INSERT: Clears the current table and restores it to the desired state.
• Why Restore a Table? :
• Restoring a table to a previous state helps recover from accidental changes or deletions.
• It ensures data integrity and consistency.
• Real-World Application :
• In production systems, restoring data mitigates the impact of errors.

Additional Notes:

• Use transactions to ensure atomicity during restoration.
• Test restoration procedures in a non-production environment first.
• Important Considerations:
• Communicate with stakeholders before performing restoration.

For more Practice: Solve these Related Problems:

• Write a SQL query to restore the Employees table to its state as of January 1, 2023, using temporal data.
• Write a SQL query to revert the Products table to a previous state after accidental data deletion.
• Write a SQL query to recover the Orders table to its state at the end of the last fiscal year for reporting purposes.
• Write a SQL query to restore a Customers table to a specific timestamp to resolve data inconsistencies.

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Previous SQL Exercise: Archiving Old Records from a History Table.
Next SQL Exercise: Adding a New Column to a Temporal Table.