Which type of JOIN returns only the rows where there is a match in both tables?
- INNER JOIN
- LEFT JOIN
- RIGHT JOIN
- FULL OUTER JOIN
An INNER JOIN returns only the rows where there is a match in both tables. It combines records from two tables based on a common column and includes only the rows with matching values in both tables. Rows with no matching values are excluded from the result set.
PHP provides a function named ________ to get the current date and time.
- current_datetime()
- time_now()
- date_time_now()
- date()
PHP's date() function is used to get the current date and time. It allows you to format the date and time in various ways as per your requirements.
Why is it recommended to avoid using the @ error suppression operator in PHP?
- It enhances code readability
- It prevents the error from occurring
- It improves error handling
- It makes code execute faster
The '@' operator suppresses error messages, making it hard to diagnose issues. It's best to handle errors explicitly for better debugging and code quality.
What is the primary difference between "overloading" and "overriding" in PHP OOP?
- Overloading is used to create multiple methods with the same name but different parameters.
- Overriding is used to create multiple methods with the same name but different parameters.
- Overloading allows you to define a new class that inherits from an existing class.
- Overriding allows you to create a new class that inherits from an existing class.
Overloading is about using the same method name with different parameters within the same class, while overriding is about providing a new implementation of a method in a child class.
To ensure security, before saving an uploaded file, which of the following PHP functions can be used to check if the uploaded file is an expected type?
- file_exists()
- is_uploaded_file()
- file_get_contents()
- mime_content_type()
The correct function to check the uploaded file's type is mime_content_type(). This function retrieves the MIME type of a file, which is crucial for security, as it helps prevent malicious file uploads.
You are reviewing a colleague's PHP code and notice they are using raw SQL statements with user input directly in the query. What potential issue does this introduce?
- SQL Injection vulnerabilities
- Improved query performance
- Better code readability
- Enhanced database compatibility
Using raw SQL statements with user input directly in the query introduces SQL Injection vulnerabilities, a major security risk.
Which network type spans a large geographic area, often connecting multiple cities or even countries?
- LAN
- MAN
- PAN
- WAN
WAN (Wide Area Network) is a network that covers a broad area, connecting multiple LANs that might be on opposite sides of the world. It can span cities, states, or even countries. The internet is the largest example of a WAN.
The PHP function that compares two arrays and returns the differences is called ________.
- array_diff()
- array_merge()
- array_intersect()
- array_unique()
The array_diff() function in PHP compares two arrays and returns the differences between them, providing a useful tool for array comparison and manipulation.
A class that cannot be instantiated and is intended to be inherited by other classes is known as a ________ class.
- 'abstract'
- 'final'
- 'static'
- 'interface'
An 'abstract' class in PHP is meant to be inherited by other classes. It can't be instantiated on its own and often contains abstract methods to be implemented by child classes.
Which PHP function can be used to strip tags from a string, often used to prevent XSS attacks?
- strip_tags()
- htmlspecialchars()
- htmlentities()
- xss_clean()
strip_tags() is used to remove HTML and PHP tags from a string, making it a useful tool for preventing cross-site scripting (XSS) attacks.