Bill Talada - Tuesday, May 16, 2017 5:42 AM
No worries. People honestly disagree all the time.
I'll still push back a little on this one. Clustered indexes are special (one might even say unique) in that they define the storage of the data, not simply a set of keys. And yeah, technically nonclustered indexes are unique at the leaf level, but only by virtue of the fact that they have the unique key values of the clustered index stored with them (or the RID for heaps). Before writing any of this, I checked Kalen Delaney's book to validate it, and she emphasizes the unique nature of clustered indexes as well (yeah, arguing from authority sucks, but I know I screw up a lot, so I validate where I can).
You do make a valid point though.
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