Home Forums SQLServerCentral.com Articles Requested PK v Unique Index RE: PK v Unique Index

  • February 21, 2015 at 8:08 am

    #1779117

    Eirikur Eiriksson (2/21/2015)

    Jeff Moden (2/21/2015)

    I guess my point is that while there is the difference in Nullability, an NC-PK isn't really going to have any I/O advantage over a Unique NCI as the user thinks. The confusion between "PK" and "Clustered" may be exactly what is article-worthy here because a lot of folks think that a PK has to be the Clustered Index.

    Good point! Would it be worth while touching on the storage difference between CL-PK vs. NC-PK, Unique Index and Unique Constraint or rather that the latter three are all implemented as NC indices? Somehow have the recollection that this has already been covered.

    😎

    Heh... just about everything has already been covered on this site in the form of an article. I sometimes have to remind myself that there's nothing wrong with a fresh perspective. For example, I was really nervous about getting "bad marks" from heavy hitters that already knew what a Tally Table was when I wrote the article on the subject but I also knew that a lot of folks still didn't know what it was. Of those that did, a lot of people didn't understand how it worked nor did they have the understanding that a SELECT is actually like a loop.

    The other thing is that a lot of folks don't say "Today, I'm going to sit down and learn about the differences in the types of indexes" but they will read an article that pops up in the SSC headlines. That's why Steve republishes certain articles on Fridays.

    To answer your questions, yes. I believe that such an article as you've described, especially if it were geared to freshman understanding, is exactly the kind of article I thing Steve is looking for based on the question that he said he received and some of the posts that we continue to see. Of course, it should focus on the question that Steve asked... "PK vs Unique Index".

    I'm actually out of line here, though, because I've taken to speaking for Steve without asking. With that point in mind...

    Steve, is THAT what you're thinking about for an article here?

    --Jeff Moden

    RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
    First step towards the paradigm shift of writing Set Based code:
    ________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

    Change is inevitable... Change for the better is not.

    Helpful Links:
    How to post code problems
    How to Post Performance Problems
    Create a Tally Function (fnTally)