How can you specify a default value for a function argument in PHP?
- By using the = default syntax.
- By using the : syntax.
- By using the ? syntax.
- By using the ?? syntax.
In PHP, you can specify a default value for a function argument by using the ? syntax before the argument name. This allows the argument to have a default value of null if not provided.
Which of the following is NOT a benefit of using bound parameters with prepared statements?
- SQL injection is prevented
- Improved performance
- Code readability is enhanced
- Data integrity is compromised
Using bound parameters with prepared statements helps prevent SQL injection, improves performance, and enhances code readability. It does not compromise data integrity.
The combination of multiple conditions in a JOIN operation is often facilitated by the ________ clause.
- WHERE
- GROUP BY
- ON
- HAVING
In SQL, the combination of multiple conditions in a JOIN operation is facilitated by the 'ON' clause. It specifies the conditions that must be met for rows to be combined across tables. This is different from the 'WHERE' clause, which filters rows before the JOIN, and 'GROUP BY' and 'HAVING,' which are used for aggregation.
You've been tasked with improving the security of an existing web application. Upon review, you notice that the application doesn't validate or sanitize user input before processing. Which potential vulnerabilities could this introduce?
- SQL Injection, Cross-Site Scripting (XSS), Command Injection, and more
- Better User Experience, Improved Performance, Data Integrity
- Enhanced Scalability, Improved Caching, Reduced Latency
- No Significant Impact on Security
Failing to validate and sanitize user input can introduce serious vulnerabilities like SQL Injection, XSS, Command Injection, and more. It can compromise the application's data, security, and integrity. The other options may bring some benefits, but the security risks outweigh them.
When uploading a file in PHP, which array key of the $_FILES superglobal gives the temporary location of the uploaded file?
- tmp_name
- name
- temp_location
- uploaded_file
The 'tmp_name' key in the $_FILES superglobal array contains the temporary location of the uploaded file on the server. This is important for processing and moving the file.
In the context of password hashing in PHP, what does "salting" mean?
- Adding salt to food
- Increasing the password length
- Mixing a unique value with the password
- Encrypting the password using SHA-256
"Salting" in password hashing involves mixing a unique value with the user's password before hashing to enhance security and prevent rainbow table attacks.
In the context of form validation, what does the term "sanitization" refer to?
- Removing malicious code
- Validating user credentials
- Cleaning and formatting data
- Authenticating the user
Sanitization in form validation involves cleaning and formatting user input data to remove harmful or unwanted characters, ensuring it's safe for processing.
Consider a scenario where you're building a CMS and you want to log errors to a specific file. Which PHP functions would be most suitable to open and write to this file?
- fopen() and fwrite()
- readfile() and copy()
- file_get_contents() and file_put_contents()
- file() and fwrite()
To open and write to a specific file in PHP, you should use fopen() to open the file and fwrite() to write to it. These functions offer fine-grained control over file handling, crucial for logging errors.
To ensure an uploaded file is not malicious, one should validate the file's ________ before saving it.
- File extension
- File size
- File name
- MIME type
The correct option is "MIME type." This is crucial because a file's MIME type provides information about its content, allowing you to verify that the uploaded file matches its claimed type and is not malicious.
How can you prevent the inheritance of an exception class in PHP?
- Declare the exception class as 'final'
- Use 'private' inheritance
- Implement 'protected' inheritance
- Use 'static' keyword inheritance
In PHP, you can prevent inheritance of a class by declaring it as 'final.' This ensures that no other class can extend it. Exception classes are often made final to prevent further customization or accidental overriding of their behavior.