How can PHP developers troubleshoot issues with retrieving specific data, such as passwords, from a database using PHP code?

When retrieving specific data, such as passwords, from a database using PHP code, developers should ensure they are using secure methods to access and handle sensitive information. One common issue is not properly sanitizing user input or using prepared statements to prevent SQL injection attacks. To troubleshoot issues with retrieving passwords from a database, developers should check the SQL query for errors, verify the database connection, and ensure the correct column name is used. 

// Example PHP code snippet to retrieve a password from a database
$username = $_POST['username'];
$password = $_POST['password'];

// Establish a database connection
$connection = new mysqli('localhost', 'username', 'password', 'database_name');

// Check for connection errors
if ($connection->connect_error) {
    die("Connection failed: " . $connection->connect_error);
}

// Prepare and execute a SQL query to retrieve the password for the given username
$query = $connection->prepare("SELECT password FROM users WHERE username = ?");
$query->bind_param("s", $username);
$query->execute();
$query->bind_result($stored_password);

// Fetch the result and verify the password
if ($query->fetch()) {
    if (password_verify($password, $stored_password)) {
        echo "Password matched!";
    } else {
        echo "Invalid password!";
    }
} else {
    echo "Username not found!";
}

// Close the database connection
$connection->close();

Keywords

PHP database data retrieval troubleshooting passwords

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