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.
Consider a scenario where you want to retrieve a list of employees and their assigned projects. However, some employees are not assigned to any project. Which type of JOIN would be best suited to get this information without omitting any employee?
- LEFT JOIN
- INNER JOIN
- RIGHT JOIN
- FULL OUTER JOIN
A LEFT JOIN retrieves all rows from the left table (employees) and the matching rows from the right table (projects). It includes employees with no matching projects, meeting the requirement.
The function in PHP that converts a JSON string into a PHP object is ________.
- json_decode()
- json_encode()
- json_parse()
- json_serialize()
To convert a JSON string into a PHP object in PHP, you should use the 'json_decode()' function. It parses the JSON data and creates a PHP object.
Why is it advisable to use exit() or die() after triggering a user-level error in PHP?
- To immediately halt script execution on error
- To allow the script to continue running, ignoring the error
- To provide a detailed error message to the user
- To log the error and continue script execution
Using exit() or die() after a user-level error is advisable because it immediately halts the script execution, preventing further processing that may lead to undesirable consequences due to the error.
What is the primary purpose of the error_reporting() function in PHP?
- To hide errors
- To display PHP version information
- To set the error reporting level
- To suppress error messages
The error_reporting() function is used to set the error reporting level, allowing developers to control which errors are displayed, aiding debugging.
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.
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.
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.
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.
In PHP, to ensure that a method in a child class has the same name, number, and type of arguments as a method in its parent class, you use the ________ keyword.
- 'new'
- 'extends'
- 'this'
- 'private'
In PHP, the 'extends' keyword is used to create a child class that inherits properties and methods from its parent class. It enforces method signature conformity.
What does the PHP array_merge() function do?
- Combines two or more arrays into one
- Multiplies elements of two arrays
- Checks if an array is empty
- Sorts the elements of an array
The array_merge() function in PHP combines two or more arrays into a single array, preserving the keys and their corresponding values from all input arrays.
How do you define a constant in PHP?
- define('MY_CONSTANT', 'constant value');
- $constant('MY_CONSTANT')
- constant('MY_CONSTANT')
- MY_CONSTANT = 'constant value';
In PHP, you define a constant using the define function. The correct syntax is define('CONSTANT_NAME', 'constant_value').