How can i check for duplicate entry before i insert?

hello,

I am using this code to insert into database:

$query="INSERT INTO `web` VALUES ('', '".$titleweb."', '".$user_no."')";
mysql_query($query);
	
    echo mysql_error();
    $c++;
   }
  }

PHP:

I do not want to insert dublicate entries. If I have an entry in ".$user_no." I do not want to have the same entry.

forexample this is my database:

id titleweb user_no
1 test 13
2 yyu 18
3 rfrf 21

If i want to insert an entry with user_no 13 it should not let me enter because i`ve already have one in database.

 

you can change the field in your table to be unique and then the query won't be inserted.

if you don't, just do a query before for getting the user id and check if it exists..

 

Use a SELECT query and then the PHP mysql_num_rows function, such as this:-

$result = mysql_query ("SELECT * FROM tablename WHERE user_no  = 'whatever');
$num_rows = mysql_num_rows($result);

// They already have a user number

if ($num_rows > '0')
{
Do this
}{

Code (markup):

Hope this helps,


Jonathan

 

Don't do this - it's a waste of a query. Even if you did need do that, you'd probably be better using COUNT in the sql syntax to save on calling mysql_num_rows.

Do what this yoavmatchulsky said - it's far more efficient.

 

Thank you for the replies. I decided to make that field unique. it will be much easier for future.

thanks again