PHP Set 5

Question 1

What are superglobal variables?

Answer 1

Built-in variables that are always available in all scopes so you can access them from any function, class, or file without needing to do anything special

Question 2

What is the $GLOBALS superglobal variable?

Answer 2

A variable that is used to access global variables from anywhere in the PHP script.
All globals are stored in $GLOBALS[index] where index is the name of the variable

Question 3

What is the $_SERVER superglobal variable?

Answer 3

Contains information about headers, paths, and script locations
1. $_SERVER[‘SERVER_ADDR’] Returns the IP address of the host server
2. $_SERVER[‘SERVER_NAME’] Returns the URL of the host server
3. $_SERVER[‘REQUEST_METHOD’] Returns the request method used to access
the page.
4. $_SERVER[‘REMOTE_ADDR’] Returns the IP address from where the user is
viewing the current page
5. $_SERVER[‘SERVER_PORT’] Returns the port on the server machine

Question 4

What is the $_REQUEST superglobal variable?

Answer 4

Used to collect data after submitting an HTML form

Question 5

What is the $_POST superglobal variable?

Answer 5

Used to collect form data after submitting an HTML form with method=”post”
Can be used for connecting to a database

Question 6

What is the $_GET superglobal variable?

Answer 6

Used to collect form data after submitting an HTML form with method=”get”
Can be used for connecting to a database

Question 7

What is the $_FILES superglobal variable?

Answer 7

Contains all file information that has been uploaded to the current script via the HTTP POST method
Ex:
1. $_FILES[‘userfile’][‘name’]; The original name of the file on the client machine.
2. $_FILES[‘userfile’][‘size’]; The size, in bytes, of the uploaded file.
3. $_FILES[‘userfile’][‘error’]; The error code associated with this file upload.

Question 8

What is a POST method upload?

Answer 8

Lets people upload text and binary files. Uses PHP’s authentication and file manipulation functions so you have full control over who is allowed to upload and what is to be done with the file once it is uploaded.

Question 9

What is the $_ENV superglobal variable?

Answer 9

Allows you to access environment variables
Ex: $_ENV[“USER”]=”Admin”
echo .$_ENV[“USER”]

Question 10

What is a cookie?

Answer 10

A piece of data from a web server that is stored within a web browser for the web server to recognize a web user

Question 11

How do you create a cookie?

Answer 11

Using the setcookie() function
setcookie(name, value, expire, path, domain, secure, httponly);
Only the name parameter is mandatory, the rest are optional

Question 12

When is the cookie sent from the browser to the server?

Answer 12

Every time the same computer requests a page, it will send the cookie too so the server can identify the user

Question 13

How can you delete a cookie?

Answer 13

Use the setcookie() function with an expiration date in the past

Question 14

What is the $_COOKIE superglobal variable?

Answer 14

Used to access cookies
$_COOKIE[$cookie_name]

Question 15

What is a session?

Answer 15

A global variable stored on the server. Each session is assigned a unique ID which is used to retrieve stored values.
When a session is created, a cookie containing the session ID is stored on the user’s computer and is returned with every request to the server.
Session values are automatically deleted when the browser is closed

Question 16

What is the difference between a session and a cookie?

Answer 16

Sessions can store relatively large data compared to cookies

Question 17

When should you use a session?

Answer 17

1. When you want to pass values from one page to another
2. When you want to store important information more securely on the server
3. When you want an alternative to cookies for browsers that do not support cookies
4. When you want to store global variables in a more efficient and secure way compared to passing them in a URL
5. When you’re developing an application that needs to store temporary information larger than 4KB

Question 18

How do you start a session?

Answer 18

Using the session_start() method

Question 19

What is the _$SESSION superglobal variable?

Answer 19

An associative array that contains session variables available to the current script

Question 20

How do you delete a session?

Answer 20

Using the session_destroy() and unset() functions
Ex: session_destroy();
unset($_SESSION[“data”]);