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Posted by Andy Hassall on 06/25/05 16:12
On Fri, 24 Jun 2005 08:54:33 -0400, "matt" <guest@guest.com> wrote:
>Hey everyone. I've been doing some php/mysql programming for a while, but i
>don't know if i've been doing this the correct way. if i have a table that
>i would like to know if it contains 1 particular record, what is the best
>way of doing it? There should not be more than one instance of it, and it
>could only be in one row. Specifically, i want to know if an email address
>is in the database.
>
>I've been doing a "SELECT * FROM email WHERE address = '$address'"; and then
>using mysql_num_rows() to see if there if it is greater than zero. is there
>a command to see if that address exists, such as returning TRUE or FALSE.
That's already a reasonable approach, and you won't get very much shorter than
that. Another one is to "select count(*) ..." and fetch the single row it'll
return - that'll be either 0 or 1 which you can use directly in PHP as 0 ==
false, 1 == true.
What are you using this test for? If you're checking if an email address is
already in the table immediately before doing an INSERT, then you should
instead use a unique constraint on the table and let MySQL handle it - this
avoids race conditions, and is quicker since it eliminates a roundtrip to the
database.
--
Andy Hassall / <andy@andyh.co.uk> / <http://www.andyh.co.uk>
<http://www.andyhsoftware.co.uk/space> Space: disk usage analysis tool
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