Cdbcachedependency With Sql Query That Returns Null

I’m using data caching with CDbCacheDependency. If my SQL query returns null, does it use “null” as the cache key and cache it so all other queries that return null get served the same cached result? Or if the query returns null does it never cache it?

  1. The cache key can not be the result of the query !

  2. Once cached, the result is cached of course!