A_GLOBAL_ID column in ROOT_1 table is null in CMDB

I am  trying to relate softwares with their corresponding hosts in CMDB for which I am writing a query that joins INSTALLED_SOFTWARE_1 view with ROOT_1 view ON INSTALLED_SOFTWARE_1.A_ROOT_CONTAINER = ROOT_1.A_GLOBAL_ID.

But A_GLOBAL_ID column is null in ROOT_1 table. I thought ROOT_1 table stores global ID for all objects and can not be null.

What could be the reason for A_GLOBAL_ID to be null ?

Do I need to enable any setting in HP UD to populate this column?

Is there any other column in ROOT_1 or other table that could be used in place of A_GLOBAL_ID


Any help would be greatly appreciated.