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From:Paul DuBois Date:June 14 1999 6:01pm
Subject:Re: what's faster: a join or searching a column with the %
wildcard?
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At 10:34 AM -0700 6/14/1999, albert braun wrote:
>Yes. I see that now. Thanks for pointing that out.
>
>One thing I find a little scary is that you can trash the set column's data
>if you redefine
>the set and make a mistake. That is, if for some reason you redefine the set
>and forget to include
>all the set vars you had before - the rows that have those vars won't have
>them any more. Arguably
>that's exactly how it should be. But one must be careful. I wish the mysql
>client would inform me
>and give me a chance to back out before it removed the existing set column's
>values. Still, it's a powerful
>feature.

It's certainly not something you should try by just typing in the
ALTER TABLE statement manually.  I'd do DESCRIBE tbl_name and catch
the output in a file.  That gives you the existing SET definition.
Then I'd edit the file to produce the ALTER TABLE statement I wanted.
I suppose a mistake is still possible, but it's a lot less likely
when you start with the column definition that MySQL itself provides.

>
>Benjamin Pflugmann wrote:
>
>> Hi!
>>
>> On Fri, Jun 11, 1999 at 12:51:41PM -0700, albert@stripped wrote:
>> > Yes, I think the idea of using a set is a good one. That's really
>> > helpful. I guess sets are a little inflexible because you can't add
>> > an element to the definition later, but I think that's the price I
>> > pay for their efficiency.
>>
>> That's not quite correct. It true that SETs are less flexible than a
>> solution with tables, but you can add elements afterwards. Have a look
>> at the ALTER TABLE syntax in the manual.
>>
>> Bye,
>>
>>         Benjamin.

--
Paul DuBois, paul@stripped
Northern League Chronicles: http://www.snake.net/nl/
Thread
what's faster: a join or searching a column with the % wildcard?albert braun11 Jun
  • RE: what's faster: a join or searching a column with the % wildcDon Read11 Jun
  • Re: what's faster: a join or searching a column with the % wildcard?Benjamin Pflugmann11 Jun
  • Re: what's faster: a join or searching a column with the % wildcard?albert braun11 Jun
    • Re: what's faster: a join or searching a column with the % wildcard?Benjamin Pflugmann12 Jun
    • SET vs Join (was: what's faster: a join or searching a columnwith the % wildcard?)chas14 Jun
      • Re: SET vs Join (was: what's faster: a join or searching a column with the % wildcard?)Roger Smith14 Jun
        • Re: SET vs Join (was: what's faster: a join or searching a column with the % wildcard?)Blake Binkley15 Jun
      • Re: SET vs Join (was: what's faster: a join or searching a column with the % wildcard?)Roger Smith14 Jun
      • UpgradingRoger Smith15 Jun
        • Re: UpgradingPaul DuBois15 Jun
        • multiple key conundrum.chas15 Jun
      • Re: multiple key conundrum.Christian Mack16 Jun
        • Re: multiple key conundrum.chas27 Jun
      • Re: SET vs Join (was: what's faster: a join or searching a column with the % wildcard?)Benjamin Pflugmann20 Jun
      • Re: multiple key conundrum.Christian Mack15 Jul
  • Re: what's faster: a join or searching a column with the % wildcard?albert braun14 Jun
    • Re: what's faster: a join or searching a column with the %wildcard?Paul DuBois14 Jun