What are common mistakes made when writing PHP scripts for database operations like insertion and deletion?

One common mistake is not sanitizing user input, which can lead to SQL injection attacks. To prevent this, always use prepared statements with parameterized queries when interacting with the database.

// Correct way to insert data into a database using prepared statements
$stmt = $pdo->prepare("INSERT INTO users (username, email) VALUES (:username, :email)");
$stmt->bindParam(':username', $username);
$stmt->bindParam(':email', $email);
$stmt->execute();
```

Another mistake is not handling errors properly, which can result in unexpected behavior or security vulnerabilities. Always check for errors after executing a query and handle them appropriately.

```php
// Correct way to handle errors when executing a query
$stmt = $pdo->prepare("DELETE FROM users WHERE id = :id");
$stmt->bindParam(':id', $id);
if ($stmt->execute()) {
    echo "Record deleted successfully";
} else {
    echo "Error deleting record: " . $stmt->errorInfo();
}