v.25.4New Feature

Allow changing a database comment

Allow changing a database comment. Closes #73351 ### Documentation entry for user-facing changes. #75622 (NamNguyenHoai).
Allows users to change the comment of an existing database in ClickHouse.

Why it matters

This feature addresses the limitation where database comments were immutable after creation. By enabling comment updates, users can better document and describe their databases over time, improving metadata management and clarity.

How to use it

Users can update a database comment by using the ALTER DATABASE statement with the COMMENT clause, for example:

ALTER DATABASE db_name COMMENT = 'New comment';