为什么这个PDO Insert执行两次？

Question

This has been inserting each line from the csv into the database twice, and now today three times. Nothing else I put in the loop happens more than it should.

$file_handle = fopen("uploads/numbers.csv", "r");    
$stmt = $db->prepare("INSERT INTO database
(firstname,lastname,phonenumber) VALUES
(:field1,:field2,:field3)");

while (($line_of_data = fgetcsv($file_handle, 1000, ",")) !== FALSE) 
{
$stmt->execute(array(':field1' => $line_of_data [0], ':field2' => $line_of_data[1], ':field3' => $line_of_data[2]));
}

Answer 1

Setup a proper primary key on database. Either (firstname, lastname) or (firstname, lastname, phonenumber) depending on the usage. Ta-da, no more duplicates.

I'm going to assume James was right in the columns by the fact that the CSV contains preexisting data in the database, but either way, a primary key will prevent duplicates.

If you use the firstname, lastname key and you want to have the script be able to update the phone number, you could use REPLACE instead of INSERT.