Reference qual conditions: "is" vs "is a" - whats the difference?

[scottatah]

As I was replicating part of our Incident form in the New Call module, I viewed the dictionary of our Closure Configuration Item field to look at the Reference Qual Conditions.   They're basically limiting the CI choices to various classes.   What is weird, is I've discovered that when you choose class, your condition has choices of:

Class is

Class is not

Class is a

Class is anything

My question is whats the difference between "Class is" and "Class is a"??

example:

Class is Computer               vs                   Class is a Computer

How would those differ?

[marcguy · Accepted solution]

Hi,

I believe 'is' will use exact class, i.e. is exactly this class and no other extended class will display.

and 'is a' will use this class plus any class that extends this class already.

i.e. is a cmdb_ci_netgear would give you all network devices plus any records from tables that extend that class.

Personally I prefer to use INSTANCE OF

Reference Qualifiers - ServiceNow Wiki

[scottatah]

After flipping back to our production instance (Calgary) where it's listed in code using INSTANCEOF I came to the same conclusion.

Your explanation is much better than mine thouhg.   Thank you!