Question

I have an array I want to check whether the username and Email values exists in database, if it does not exist insert the username and email values in the database. Using Multi insert since there are around 80000 inserts to be preformed.

$arr1 = Array
(
    [0] => Array       ( [Username] => uname1,  [Email] => email1  )

    [1] => Array   (  [Username] => uname2,  [Email] => email2  )

    [2] => Array   (  [Username] => uname3,  [Email] => email3 )

)

Answer 1

A SQL statement with 80000 INSERTs will function slower than 80000 separate INSERTs, because the monolithic, multi-INSERT SQL statement-string won’t need to be built. For overwriting existing rows, you will need a primary key to ensure that duplicate records are overwritten: http://dev.mysql.com/doc/refman/5.1/en/replace.html.

foreach ($arr1 as $user){
    $sql = "REPLACE INTO `users` SET `Username`='" . mysql_escape_string($user["Username"]) . "', `Email`='" . mysql_escape_string($user["Email"]) . "'";
    mysql_query($sql);
}

My code assumes that Username is the primary key. If not, add to the SET clause to include the primary key. If Username is your primary key, consider using an integer-based one as primary keys based on strings are slow.