What potential pitfalls should be avoided when working with PHP and MySQL databases?

One potential pitfall to avoid when working with PHP and MySQL databases is SQL injection attacks. To prevent this, always use prepared statements with parameterized queries instead of directly inserting user input into SQL queries. 

// Example of using prepared statements to prevent SQL injection

// Assume $conn is a valid MySQL database connection

// Prepare a SQL statement with a placeholder for the user input
$stmt = $conn->prepare("SELECT * FROM users WHERE username = ?");

// Bind the user input to the placeholder in the SQL statement
$stmt->bind_param("s", $username);

// Set the user input
$username = $_POST['username'];

// Execute the prepared statement
$stmt->execute();

// Get the result set
$result = $stmt->get_result();

// Fetch the data from the result set
while ($row = $result->fetch_assoc()) {
    // Process the data
}

// Close the prepared statement
$stmt->close();

Keywords

SQL injection PDO prepared statements data validation error handling

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