What exactly is GUID? Why and where I should use it?

Question

What exactly is GUID? Why and where I should use it?
I\'ve seen references to GUID in a lot of places, and in wikipedia, but it is not very clear telling you where to

Answer 1

GUID stands for "Globally Unique Identifier" and you use it when you want to have, erm, a Globally Unique Identifier.

In RSS feeds, for example, you should have a GUID for each item in the feed. That way, the feed reader software can keep track of whether you have read that item or not. Without a GUID, it would be impossible to tell.

A GUID differs from something like a database ID in that no matter who creates an object -- you, me, the guy down the street -- our GUIDs will always be different. There should be no collisions using a GUID.

You'll also see the term UUID, which stands for "Universally Unique Identifier." There is essentially no difference between the two. UUID is the more appropriate term. GUID is the term used by Microsoft.