Using Change Data Capture (CDC) for Audit Requirements
By Tom Nonmacher
In today's data-driven world, being able to track and audit changes to your database is not just a sensible precaution, it can also be a regulatory requirement. Fortunately, SQL Server 2012, SQL Server 2014, MySQL 5.6, DB2 10.5, and Azure SQL all support a feature known as Change Data Capture (CDC), which makes this task much easier.
CDC is a feature that records insert, update and delete activity in SQL Server tables. The captured data is then stored in change tables, which provide a historical view of the data. CDC can be used to keep track of changes made to the data, making it perfect for audit requirements.
In SQL Server, CDC can be enabled at the database level with a simple T-SQL command. Before enabling CDC, ensure that the SQL Server Agent is running, as it's required for the CDC jobs. Here is an example of how to enable CDC:
USE YourDatabaseName;
GO
EXEC sys.sp_cdc_enable_db;
GO
Once CDC is enabled on the database, you can then enable it on individual tables. Here's an example of how to enable CDC on a table:
USE YourDatabaseName;
GO
EXEC sys.sp_cdc_enable_table
@source_schema = N'dbo',
@source_name = N'YourTableName',
@role_name = NULL,
@supports_net_changes = 1
GO
On the other hand, MySQL and DB2 do not have built-in CDC features like SQL Server, but they do support Binary Logging and Change Data Capture by triggers respectively, which can be used to achieve similar results. For MySQL, Binary Logging must be enabled in the MySQL configuration file (my.cnf or my.ini) and for DB2, you can create triggers on tables to capture changes.
Finally, Azure SQL Database supports CDC as of 2018. It can be enabled in a similar way as in SQL Server, but remember to enable it at both the database level and at the table level. Once enabled, changes can be viewed using the cdc.fn_cdc_get_all_changes function.
In conclusion, whether you're using SQL Server, MySQL, DB2, or Azure SQL, there are robust solutions available for capturing data changes for audit requirements. These tools provide you with the peace of mind of knowing that you can track and audit changes to your data, helping you to maintain data integrity and comply with any regulatory requirements.