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From:Paul DuBois Date:July 31 2000 12:45am
Subject:RE: The meaning of "UNIQUE idx_user_id (user_id)"
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>   -----Original Message-----
>
>   Hi,
>
>   "Actually, I can't. Do you mean that index_name is a separate column or
>        just an alias for index_col_name? The manual does have a line for the
>synta
>   x
>        of UNIQUE but it never explains it!"
>
>   Well all it means is that you can specify a name for the index. It's
>   optional because in itself it doesn't do anything. Really it's for your
>   convenience as much as anything.
>
>   "Also, optional doesn't necessarily mean implied. In fact, are you sure
>        that UNIQUE implies INDEX?"
>
>   Yes, a unique one. To perhaps confuse things, so does KEY (KEY is a
>   synonym for INDEX).
>
>   Hmm, I'm not convinced. I'd think the opposite would be preferable in
>order to allow a column to be defined as UNIQUE without it being an INDEX.
>Then again, you might be right but not because of what can be found in the
>docs.


To ensure that column values are UNIQUE would be horribly inefficient
if the column were not indexed.  You'd have to do a full table scan
every time you added or modified a column value.


I'm beginning to wonder if you're trolling.  Are you?

-- 
Paul DuBois, paul@stripped
Thread
The meaning of "UNIQUE idx_user_id (user_id)"henrydesiato30 Jul
  • Re: The meaning of "UNIQUE idx_user_id (user_id)"Paul DuBois30 Jul
    • RE: The meaning of "UNIQUE idx_user_id (user_id)"henrydesiato30 Jul
      • RE: The meaning of "UNIQUE idx_user_id (user_id)"indrek siitan30 Jul
        • RE: The meaning of "UNIQUE idx_user_id (user_id)"henrydesiato31 Jul
          • RE: The meaning of "UNIQUE idx_user_id (user_id)"indrek siitan31 Jul
  • Re: The meaning of "UNIQUE idx_user_id (user_id)"Paul DuBois30 Jul
  • RE: The meaning of "UNIQUE idx_user_id (user_id)"indrek siitan30 Jul
    • RE: The meaning of "UNIQUE idx_user_id (user_id)"henrydesiato31 Jul
Re: The meaning of "UNIQUE idx_user_id (user_id)"Nick Lindridge30 Jul
  • RE: The meaning of "UNIQUE idx_user_id (user_id)"henrydesiato30 Jul
Re: The meaning of "UNIQUE idx_user_id (user_id)"Nick Lindridge31 Jul
  • RE: The meaning of "UNIQUE idx_user_id (user_id)"henrydesiato31 Jul
    • RE: The meaning of "UNIQUE idx_user_id (user_id)"Paul DuBois31 Jul
      • RE: The meaning of "UNIQUE idx_user_id (user_id)"henrydesiato31 Jul
        • Re: The meaning of "UNIQUE idx_user_id (user_id)"Benjamin Pflugmann31 Jul
        • RE: The meaning of "UNIQUE idx_user_id (user_id)"Paul DuBois31 Jul
    • Re: The meaning of "UNIQUE idx_user_id (user_id)"Benjamin Pflugmann31 Jul
Re: The meaning of "UNIQUE idx_user_id (user_id)"Nick Lindridge31 Jul
  • RE: The meaning of "UNIQUE idx_user_id (user_id)"henrydesiato31 Jul
RE: The meaning of "UNIQUE idx_user_id (user_id)"henrydesiato31 Jul
  • RE: The meaning of "UNIQUE idx_user_id (user_id)"Paul DuBois31 Jul
Re: The meaning of "UNIQUE idx_user_id (user_id)"Nick Lindridge31 Jul
  • RE: The meaning of "UNIQUE idx_user_id (user_id)"henrydesiato31 Jul
    • RE: The meaning of "UNIQUE idx_user_id (user_id)"Paul DuBois31 Jul
    • Re: The meaning of "UNIQUE idx_user_id (user_id)"Mike Wexler31 Jul
      • Re: The meaning of "UNIQUE idx_user_id (user_id)"Paul DuBois31 Jul