Are Guids guaranteed to be unique?

Question

I\'m using Guids as primary keys in my database and was wondering if it is ever possible that a duplicate Guid might be generated. Are Guids guaranteed to be unique?

Answer 1

While each generated GUID is not guaranteed to be unique, the total number of unique keys (2128 or 3.4×1038) is so large that the probability of the same number being generated twice is very small.

You can check more info on that here.

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A possible solution to avoid duplicate guids (if you still want one) is to use the UNIQUE constraint.