What does T-SQL msdb.dbo.RestoreHistory Restore_Type NULL mean?

Question

In msdb.dbo.RestoreHistory, the Restore_Type can be NULL.

See https://docs.microsoft.com/en-us/sql/relational-databases/system-tables/restorehistory-transact-sql?view=sql-server-ver15

restore_type / char(1) / Type of restore operation

• D = Database
• F = File
• G = Filegroup
• I = Differential
• L = Log
• V = Verifyonly
• Can be NULL.

I understand what D to V stand for.

However what kind of DB restore history record would have restore type NULL?

Thanks.

Answer 1

The column is NULLable on the table, so technically that column can be NULL because no constraint enforces otherwise--that's what the docs are defining.

However, there is no scenario where you would expect SQL Server to intentionally save a NULL restore type.