re: Use PowerShell to Easily Find the Key Property of a WMI Class

Klaus Schulte — Thu, 03 Nov 2011 13:12:20 GMT

Hi Ed,

this maybe another important aspect of WMI ... a kind of "key experience" :-)

But: I don't know if you are like me and not so deeply involved in the world of WMI Qualifiers ...

The first question I had to answer for myself is: What is the meaning of the "key" qualifier = why should I bother?

Well, it looks like I'm going to find a kind of "primary key" ( Database jargon ) property that unambiguously identifies an instance of a special class needed to operate on this very special instance and no other similar , maybe even equaly named, instance. So if I want to distinguish my 10 running notepad.exe processes, I have to find the key property "handle" and use it to address a special notepad instance.

Other questions I had: "Can there be more than one key for a class?" ( YES, similar to primary indexes in DB systems )

"Are there classes without a key?" ( YES ... e.g. Singletons )

So I concluded that the key property maybe something, I might want to know in cases where many instances of a class have been created.

Klaus