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From:Paul DuBois Date:October 8 2006 9:35pm
Subject:Re: How to not repeat fields
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At 22:21 +0100 10/8/06, Deckard wrote:
>Hi,
>
>Ok, naow i have this:
>
>CREATE TABLE wl_users(wl_user_id INT NOT NULL AUTO_INCREMENT, name
>VARCHAR(255) NOT NULL, email VARCHAR(50) NOT NULL, password VARCHAR(32)
>NOT NULL, PRIMARY KEY (wl_user_id, name, email, password)) TYPE=MyISAM;
>
>and it lets repeated rows.

You have a PRIMARY KEY on all four columns in the table, so every
combination of values for those four columns is required to be unique.

Therefore, if you have repeated rows in the table, that's very strange.

I claim you don't really have repeated rows. :-)

Can you provide a test case that shows repeats?

>
>How can i avoid the repeates rows ?
>
>Best Regards,
>Deckard
>
>Paul DuBois wrote:
>>  At 22:11 +0100 10/8/06, Deckard wrote:
>>>  Hi,
>>>
>>>  How do i dreate a table, let's say:
>>>
>>>  CREATE TABLE wl_articles(wl_articles_id INT NOT NULL AUTO_INCREMENT
>>>  PRIMARY KEY, title TEXT NOT NULL,
>>>           main TEXT NOT NULL, extended TEXT NOT NULL, permalink
>>>  VARCHAR(255) NOT NULL, date DATE NOT NULL, ip VARCHAR(15), user_agent
>>>  VARCHAR(50), status INTEGER NOT NULL,
>>>                   password VARCHAR(32) NOT NULL) TYPE=MyISAM;
>>>
>>>  without allowing INSERTs to repeat rows based on certain fields, for
>>>  example, "main" and "status" ?
>>
>>  Normally, you would do this by creating a UNIQUE index on the combination
>>  of columns.  (Or you could use a PRIMARY KEY if both columns are NOT NULL.)
>>
>>  However, you cannot do what you want in this case.  Why?  Because main is
>>  a TEXT column, and TEXT columns allow a maximum of 255 initial characters
>>  to be indexed.  That means you cannot use a UNIQUE index to provide a
>  > uniqueness constraint on anything from the 256th character on.

-- 
Paul DuBois, MySQL Documentation Team
Madison, Wisconsin, USA
MySQL AB, www.mysql.com
Thread
How to not repeat fieldsDeckard8 Oct
  • Re: How to not repeat fieldsPaul DuBois8 Oct
    • Re: How to not repeat fieldsDeckard8 Oct
      • Re: How to not repeat fieldsPaul DuBois8 Oct
        • Re: How to not repeat fieldsDeckard8 Oct
          • Re: How to not repeat fieldsPaul DuBois9 Oct
            • Re: How to not repeat fieldsDeckard9 Oct
              • Re: How to not repeat fieldsPaul DuBois9 Oct
  • Re: How to not repeat fieldsMartijn Tonies9 Oct
  • Re: How to not repeat fieldsMartijn Tonies9 Oct
    • Re: How to not repeat fieldsDeckard9 Oct