Sql Server sysjobsteps step_uid列可空性

I am working on a project creating a log table of sorts for failed jobs. Since the step_id can change depending on step order, I wanted to use the step_uid as a unique identifier for a step. With that in mind, is seems that the step_uid in msdb's sysjobsteps table is a nullable column, and I am relying on that column NOT being null as of yet.I am working on a project creating a log table