Please PMJI, but I'm new to PHP but have a little experience with databases,
and I have a question:
Is there a particular reason that LIKE is used in the query? Let's say you had
the contrived alias value in the table, 'aaaaa', and one wanted to add the
alias, 'aaaa' (or fewer 'a's). Wouldn't the query misreport that the alias,
'aaaa', already exists?
I'm assuming that the number of characters in the alias can vary by some range
(e.g., 3 to 10 characters), and that:
"SELECT alias FROM tablename WHERE alias LIKE '$alias%' LIMIT 1";
becomes:
"SELECT alias FROM tablename WHERE alias LIKE 'aaaa%' LIMIT 1";
at execution-time.
Regards,
Dave
-----Original Message-----
From: Jeffrey [mailto:[EMAIL PROTECTED]
Sent: Sun 10/2/2005 3:32 AM
To:
Cc: PHP DB
Subject: Re: [PHP-DB] If syntax
See below...
Ron Piggott wrote:
>Take a look at my if ( ) syntax line below. I am wondering if I have
it
>wrong in same way. What I am trying to achieve is if the alias the
user
>enters is already found in the database I want the words "Alias
already in
>use" to be shown on the screen; otherwise "Unique alias" to be shown
on the
>screen.
>
>PRESENTLY alias already in use is what comes up all the time.
>
>Ron
>
>
>mysql_connect(localhost,$username,$password);
>@mysql_select_db($database) or die( "Unable to select database");
>$query="SELECT * FROM tablename WHERE alias LIKE '$alias%'";
>
>if (mysql_query($query))
>
>{
>
>echo "Alias already in use";
>
>} else {
>
>echo "Unique alias";
>
>mysql_close();
>
>}
>
>
>
Whether or not there are any matches, you will always have a database
query - hence mysql_query($query) will always produce something
Instead you need to see if there are any matches to your variable.
Also, "SELECT * FROM [some_table] is tremendously inefficient when you
only need to count results. You are basically calling up every result in
your entire table just to see if a single column entry matches a
variable.
I would suggest something like..
mysql_connect(localhost,$username,$password);
@mysql_select_db($database) or die( "Unable to select database");
$query="SELECT alias FROM tablename WHERE alias LIKE '$alias%' LIMIT 1";
$result=(mysql_query($query))
if (mysql_num_rows($result)==1)
{
echo "Alias already in use";
} else {
echo "Unique alias";
mysql_close();
}
Good luck,
Jeffrey
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