Database: Change Tracking
Change tracking is a feature in databases that allows you to track changes to data over time. This can be useful for a variety of purposes, such as auditing, data synchronization, and conflict resolution.
Code Snippets
Here is an example of how to enable change tracking in SQL Server:
ALTER DATABASE AdventureWorks
SET CHANGE_TRACKING = ON
(CHANGE_RETENTION = 2 DAYS, AUTO_CLEANUP = ON)
Sample Examples
Let's say we have a table called Customers with columns CustomerID and CustomerName. We can enable change tracking on this table using the following SQL query:
ALTER TABLE Customers
ENABLE CHANGE_TRACKING
WITH (TRACK_COLUMNS_UPDATED = ON)
Now, whenever a change is made to the Customers table, the change tracking system will log the details of the change.
Common Use Cases
Some common use cases for change tracking include:
- Auditing changes to data
- Replicating data between databases
- Implementing conflict resolution in distributed systems
Importance in Interviews
Understanding change tracking is important for database developers and administrators, as it is a commonly used feature in many database systems. Employers may ask about your experience with change tracking in interviews, so it's important to be familiar with the topic.
Conclusion
Change tracking is a powerful feature in databases that can help you track changes to your data over time. By enabling change tracking, you can improve auditing, data synchronization, and conflict resolution in your database system.
