FAQ

Is SQLCLR still supported by Microsoft?

Yes. CLR integration remains a supported SQL Server feature, including in current releases. What changed over time is the security posture — "CLR strict security" (2017+) requires assemblies to be signed or explicitly trusted.

Can I use .NET 8 / .NET Core?

No. SQL Server hosts the .NET Framework CLR (CLR 4). Assemblies must target .NET Framework. If your logic needs modern .NET, host it outside the database (a service, an external script, or an Azure Function) and call it from your application layer.

Is CLR faster than T-SQL?

For set-based data access: no — T-SQL wins, usually by a lot. For row-by-row computation — string parsing, regex, custom aggregation, numeric algorithms — CLR is often dramatically faster than the T-SQL equivalent (scalar UDFs, WHILE loops, cursor logic).

Does CLR work on Linux SQL Server?

Yes, with limits: SQL Server on Linux supports SAFE assemblies. EXTERNAL_ACCESS and UNSAFE are restricted compared to Windows.

Does CLR work in Azure SQL Database?

Azure SQL Managed Instance supports CLR. Azure SQL Database (single database / elastic pool) does not.

Can a bad assembly crash my server?

The hosting model is designed to prevent it: SQL Server controls memory and threading, and will unload an app domain rather than fail the process for SAFE code. UNSAFE assemblies, by definition, can do anything — which is why they require the highest trust to register.

Where does my DLL live after deployment?

Inside the database. CREATE ASSEMBLY copies the bytes into sys.assembly_files; the file on disk is no longer needed and is not consulted again.