Question

How can I check before storing in mysql wether in array 1 of the variables already exist in my database. if $explode[$i] exist go to next. if not exist run the code below!

Here is my code in php:

$request_user_ids = $_GET['req'];
     $explode = explode(',',$request_user_ids);
     for ($i=0; $i<count($explode);$i++){

  $result = mysql_query("
          INSERT INTO fbinvite (memberid, fbsender, fbempfang, regdatum, fbreturn) 
          VALUES(NULL, '".$userid."', '".$explode[$i]."', NOW(), '0')");

How can I do that there are no double inserts.

Answer 1

First of all make the relevant set of attributes to be primary key or unique index of the table.

Then you have several options:

• blindly use INSERT IGNORE INTO fbinvite ..., if you simply want to ignore duplicated data OR
• check if entry exists: SELECT memberid FROM fbinvite WHERE some_attr1 = $explode[...] AND some_attr2 = $explode[...]; and continue appropriately:
  • if entry doesn’t exist, insert it to the table: INSERT INTO fbinvite ...
  • if entry exists:
    • show message to the user OR
    • update existing entry: UPDATE fbinvide ... WHERE ...
  • insert OR update at once: INSERT ... ON DUPLICATE KEY UPDATE ...