Search before Adding (PHP/Mysql)

thatshanekid

Hi.
Well i've been trying to make a little script for a mates website.
What it does, you type something into a text field, it searches the database for the value in that textfield, if there is an entry already like that in the database, it will not add it, if there isn't, it will add into the database.
Kinda like a Registration form (But its not, same principle)

Here is my code (Some bits edited out)

<?php

$dbhost = "mysql"; //Database Host
$dbuser = "###"; //Database User
$dbpass = "###"; //Database Password
$dbname = "###"; //Database Name

//connect
$db = mysql_pconnect($dbhost,$dbuser,$dbpass);
mysql_select_db("$dbname",$db); 

$searchdb="SELECT * FROM ### WHERE keywords ='$_POST[###]';
$result=mysql_query($searchdb);
$num=mysql_num_rows($result);

if ($num = 0){
    echo "No results found";
}else{
echo "Found results";
}

?>

Now im sure i haven't missed any ; because i have looked over it, and i have viewed tutorials online that use this code almost EXACT (Just changed entires etc).

But here is the error:

Parse error: syntax error, unexpected T_STRING in /hosted/subs/ulmb.com/t/h/###/public_html/### on line 19

Eh, im probably being an idiot again lols. I need to learn errors asap.
But thanks.

johanafm

Using an editor that has syntax highlighting is very useful, and the same benefit is given for php code by the php tags of this forum over the code tags.

See the first red ;? It's red because it's part of a string, and it shouldn't be. Hence, you're missing a closing string delimiter.

$dbhost = "mysql"; //Database Host
$dbuser = "###"; //Database User
$dbpass = "###"; //Database Password
$dbname = "###"; //Database Name

//connect
$db = mysql_pconnect($dbhost,$dbuser,$dbpass);
mysql_select_db("$dbname",$db); 

$searchdb="SELECT * FROM ### WHERE keywords ='$_POST[###]';
$result=mysql_query($searchdb);
$num=mysql_num_rows($result);

if ($num = 0){
    echo "No results found";
}else{

Also, using quotes for things like this is unnecessary.

mysql_select_db("$dbname",$db);

And finally, after $result = mysql_query(), you should ALWAYS check that you actually have a valid result resource and not boolean false, since that would break your code on the following line (mysql_num_rows(false))

$result=mysql_query($searchdb);
if ($result) {
    $num=mysql_num_rows($result);

laserlight

thatshanekid wrote:
Well i've been trying to make a little script for a mates website.
What it does, you type something into a text field, it searches the database for the value in that textfield, if there is an entry already like that in the database, it will not add it, if there isn't, it will add into the database.

One approach is to declare the relevant column as unique. Then, instead of searching before insertion, you just try and insert. If the value already exists in that column, the insertion will fail with a unique constraint violation, which you could check and inform the user (or not inform the user, but instead inform the user or log if the insertion fails due to something other than a unique constraint violation).

Although it probably does not apply to you, the advantage of this method over searching first is that between the time it takes to check that no such value exists and the time it takes to insert the value, another insertion (e.g., by another user) could have been done that inserts the same value. This race condition means that even with the check, it is possible to have duplicates because the check+insert is not atomic.