What should you do first before accessing session variables in a PHP script?
- Start the session using session_start();
- Initialize the session
- Assign values to all session variables.
- Nothing specific, you can access them directly.
Before accessing session variables in a PHP script, you should start the session using session_start();. This initializes the session and allows you to work with session variables.
Imagine a scenario where you need to calculate the factorial of a number using PHP. Which loop structure would be best suited to solve this?
- For Loop
- While Loop
- Do-While Loop
- If-Else Loop
A 'For Loop' is well-suited for tasks with a known number of iterations, like calculating a factorial, as you can control the loop using a counter variable.
Which of the following PHP functions can be used to move an uploaded file to a desired location?
- move_uploaded_file()
- copy_file()
- upload_file()
- relocate_file()
The 'move_uploaded_file()' function is specifically designed for moving an uploaded file to a desired location. It handles security checks and ensures the move is safe.
You are debugging a complex issue in a PHP application. Which tool or function might be most helpful in tracing the sequence of function calls leading to the error?
- a) echo()
- b) var_dump()
- c) debug_backtrace()
- d) set_error_handler()
c) The debug_backtrace() function is the most helpful for tracing the sequence of function calls leading to the error. It provides a backtrace of the function calls made to reach the current point, making it invaluable for debugging complex issues. The other options (a, b, d) have different purposes and are not specifically designed for this task.
In PDO, the ________ method is used to bind a value to a parameter.
- bindParam()
- exec()
- query()
- connect()
The 'bindParam()' method in PDO is used to bind a value to a parameter in a prepared statement, allowing for secure and efficient parameterized queries.
You're writing a custom exception class in PHP to handle specific types of errors in your application. Which built-in PHP class would you extend to achieve this?
- Exception
- Error
- Throwable
- CustomException (No built-in class)
To create a custom exception class in PHP, you extend the built-in Exception class. This allows you to handle specific types of errors in your application.
For secure user authentication, what additional measure can be used along with a password to enhance security?
- Two-factor authentication (2FA)
- Using a longer username
- Implementing CAPTCHA challenges
- Enforcing strong password policies
Two-factor authentication (2FA) is an additional security measure that requires users to provide two forms of identification to access their account, enhancing security.
Which PHP function is used to read the contents of a file into a string?
- file_get_contents()
- readfile()
- fopen()
- fread()
The file_get_contents() function is used to read the contents of a file into a string in PHP. It's a convenient way to work with file data as a string.
The practice of ensuring that data is clean and correct before it's processed is called data ________.
- Validation
- Encryption
- Sanitization
- Obfuscation
Data "Validation" is the process of ensuring that data is clean and conforms to predefined standards or rules before it is processed. This helps prevent incorrect or malicious data from affecting the system.
The ________ method in an exception class gets the exception message.
- getMessage()
- getExceptionMessage()
- fetchMessage()
- retrieveErrorMessage()
The correct method for retrieving the exception message in an exception class is getMessage(). This method returns a string describing the exception.