Data classification filter - MSSQL

The data classification filter is a special-purpose filter that enables SQL Server's data classification feature even for database clients that do not support it. This does not affect the clients in any way.

What it does

If a database client requests the data classification feature during the login process, then any time a query is run against a table on which data classifications have been defined, the server will return that data classification information along with the result set's metadata. It is then up to the database client to interpret that data classification information.

Some SQL Server drivers (for Node.js and Python, for instance) simply do not support this feature, which makes it almost impossible to use data classification in applications written using these drivers.

When you add the data classification filter to your Gallium Data project, it will automatically make sure that the data classification feature is always enabled on the database server side. The feature will also be enabled on the client side if the client supports it.

This means that all responses from the database will include data classification information if it is defined in the database, and that classification information will be available to the logic in your Gallium Data filters. If the database client does not support data classification, that information will be stripped from the server's response before it gets forwarded, so as not to confuse the client which would not expect it.

If you know for sure that all your database clients support data classification, this filter is unnecessary, but if you have any doubt, and you plan on using data classification in your filter logic, you should add this filter to your project just to be sure.


  • Client IPs: optional. If specified, a comma-separated (or line break separated) list of IP4 or IP6 addresses or regular expressions for IP addresses. Example:,regex:12\.34\.12\..* meaning the address as well as all addresses starting with 12.34.12.


For more background about this filter, see SQL Server data classification comes alive and the step-by-step tutorial.