Home Forums Article Discussions Article Discussions by Author Discuss content posted by Ron Johnson Understanding Indexes RE: Understanding Indexes

  • February 15, 2011 at 12:19 pm

    #1287261

    GilaMonster (2/15/2011)

    Jeff Moden (2/15/2011)

    Since I'm not an expert on indexes that you good folks are, can you confirm that the bolded statements in the above quote are, depending on whether it's a covering index or not, incorrect... or not? I realize that data is stored in the index but that data is actually used if it's a covering index.

    A nonclustered index does not just contain an address of the actual row. It contains the index key columns, any include columns defined and either the clustered index key or the RID, depending whether the base is a heap or a cluster. The clustered index key/RID can be considered the 'address' of the row.

    Thanks, Gail. I guess it was just the way it was worded in the article. I thought I knew better (according to the possibly incorrect interpretation on my part) but needed to confirm it with someone that knew for sure. As usual, you difinitely came through on the clarification. 🙂

    --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)