What Causes \"Unexplainable Fatal Error\" When Connecting to MySQL with PHP 7?

MySQL Connection Errors with PHP 7

When working with PHP and MySQL, an "Unexplainable Fatal error" may occur, indicating that the mysql_connect() function is not defined. This error can be attributed to an outdated PHP version.

The Problem:

PHP 7 has deprecated the mysql_* functions, including mysql_connect(). As a result, attempting to use these functions in PHP 7 will result in an undefined function error.

The Solution:

To resolve this issue, you need to upgrade your code to use the mysqli_* functions. Here's an example of how you can fix the issue:

<code class="php">$host = "127.0.0.1";
$username = "root";
$pass = "foobar";
$con = mysqli_connect($host, $username, $pass, "your_database");</code>

Upgrading Legacy Code:

If you are upgrading legacy PHP code, you will need to replace all occurrences of mysql_ functions with their mysqli_ counterparts. This includes functions such as mysql_query(), mysql_fetch_array(), and others.

By updating your code to use the mysqli_* functions, you will avoid the undefined function error and ensure that your code is compatible with PHP 7.

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