Why is my PHP script inserting data twice into MySQL even though I only ran it once?

PHP Running Once but Inserting Twice into MySQL Database

When running the provided code locally, you may encounter an anomaly where the database inserts two records instead of one after the script has been executed only once. This issue is particularly evident in browsers such as Opera or Chrome.

The problem arises due to a common browser behavior: requesting favicons. When a website is accessed, the browser will send a request for the script and a second request for the favicon. In your case, since the code processes every request, it attempts to insert a database record twice, resulting in duplicate entries.

To resolve this issue, you should modify your code to ensure that the insert query is executed only for specific requests, such as the initial page load. You can achieve this by utilizing the PHP $_SERVER['REQUEST_URI'] variable, which provides the requested URI of the current page. By comparing this variable to a known value (e.g., the home page URI), you can restrict the execution of the insert query to specific requests.

For instance, you can modify your code as follows:

$requestURI = $_SERVER['REQUEST_URI'];
if ($requestURI == '/index.php') {
  $sql = "INSERT INTO test_table (value, insert_time) VALUES ('testing', '" . time() . "')";
  $result = mysql_query($sql);
}

This modification ensures that the insert query will only be executed when the home page is accessed, preventing duplicate database insertions when the browser requests the favicon.

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