php Flashcards
(127 cards)
1
Q
Q1: What does PHP stand for?
A
A: PHP stands for Hypertext Preprocessor.
2
Q
Q2: Is PHP a client-side or server-side language?
A
A: PHP is a server-side scripting language.
3
Q
Q3: What are PHP files saved as?
A
A: PHP files have a .php extension.
4
Q
Q4: What platforms does PHP support?
A
A: PHP runs on Windows, Linux, Mac, etc.
5
Q
Q5: Name two popular web servers PHP supports.
A
A: Apache and IIS.
6
Q
Q6: Can PHP work with databases?
A
A: Yes, PHP supports databases like MySQL.
7
Q
Q7: What can PHP do with files?
A
A: PHP can create, open, read, write, and delete files.
8
Q
Q8: How is PHP used in forms?
A
A: It collects form data and processes it.
9
Q
Q9: How is PHP code executed?
A
A: On the server, and HTML is sent to the browser.
10
Q
Q10: What is PHP mainly used for?
A
A: Building dynamic web applications.
11
Q
Q1: What is the basic syntax for PHP?
A
A: <?php to start, ?> to end.
12
Q
Q2: Are PHP keywords case-sensitive?
A
A: No, but variables are case-sensitive.
12
Q
Q3: How do you write a single-line comment?
A
A: Using // or #.
13
Q
Q4: How do you write multi-line comments?
A
A: Using /* */.
14
Q
Q5: How should a PHP variable start?
A
A: With a $ followed by a letter or underscore.
15
Q
Q6: Can a PHP variable start with a number?
A
A: No, it must start with a letter or underscore.
16
Q
Q7: What are valid variable names in PHP?
A
A: $name, $_age, $user123.
17
Q
Q8: What happens if PHP code contains an error?
A
A: It may show a blank page or error message.
18
Q
Q9: What does echo do in PHP?
A
A: Outputs data to the screen.
19
Q
Q10: What symbol is used for variables in PHP?
A
A: The $ sign.
20
Q
Q1: What are the main data types in PHP?
A
A: String, Integer, Float, Boolean, NULL, Array, Object.
21
Q
Q2: What is a string in PHP?
A
A: A sequence of characters (e.g., “Hello”).
22
Q
Q7: What is an array in PHP?
A
A: A collection of values stored under one name.
23
Q
Q8: What are the types of arrays in PHP?
A
A: Indexed, Associative, Multidimensional.
24
Q9: What is an object in PHP?
A: An instance of a class containing data and functions.
25
Q10: How do you check a variable’s data type in PHP?
A: Using the var_dump() function.
26
Q1: What are the types of conditional statements in PHP?
A: if, if-else, if-elseif-else, switch.
27
Q2: How does an if statement work in PHP?
A: Executes code if a condition is true.
28
Q3: What does an else statement do?
A: Runs code if the if condition is false.
29
Q4: When do we use elseif in PHP?
A: To check multiple conditions after an if.
30
Q5: What is the purpose of a switch statement?
A: To select one of many code blocks to execute.
31
Q6: What keyword is used to exit a switch case?
A: break.
32
Q7: What happens if you don't use break in a switch?
A: It will continue executing the next case.
32
Q8: Can you use default in a switch statement?
A: Yes, it runs if no cases match.
33
Q9: What operator is used to compare values in conditions?
A: == (equal to).
34
Q10: What operator checks both value and type?
A: === (identical).
35
Q1: What are the loop types in PHP?
A: for, foreach, while, do-while.
36
Q2: How does a for loop work?
A: Loops a set number of times.
37
Q3: What does a foreach loop do?
A: Loops through each element in an array.
38
Q4: What is the syntax of a while loop?
A: Executes as long as a condition is true.
39
Q5: What is unique about a do-while loop?
A: Executes at least once before checking the condition.
40
Q6: What keyword is used to exit a loop?
A: break.
41
Q7: What keyword skips the current iteration?
A: continue.
42
Q8: What is an infinite loop?
A: A loop that never ends due to a missing exit condition.
43
Q9: Can loops be nested in PHP?
A: Yes, loops can be placed inside other loops.
44
Q10: How do you loop through an associative array?
A: Using the foreach loop.
45
Q1: What is a function in PHP?
A: A block of code that performs a specific task.
46
Q2: How do you define a function in PHP?
A: Using the function keyword.
47
Q3: What is the syntax for defining a function?
A: function functionName() { //code }
48
Q4: How do you call a function?
A: By using its name followed by parentheses functionName();
49
Q5: What are PHP function types?
A: Built-in and user-defined functions.
50
Q6: How do you pass arguments to a function?
A: Inside parentheses, e.g. function greet($name).
51
Q7: Can a function return a value?
A: Yes, using the return keyword.
52
Q8: What is a default function argument?
A: A preset value if no argument is passed.
53
Q9: Are function names case-sensitive?
A: No, function names are not case-sensitive.
54
Q10: What does declare(strict_types=1); do?
A: Enforces strict type checking in PHP 7+.
55
Q1: What is an array in PHP?
A: A collection of values stored under a single name.
56
Q2: What are the types of arrays in PHP?
A: Indexed, Associative, Multidimensional.
57
Q3: How do you create an indexed array?
A: $arr = array("apple", "banana", "cherry");
58
Q4: How do you access an indexed array element?
A: Using its index, e.g. $arr[0].
59
Q5: How do you create an associative array?
A: $arr = array("name" => "Salam", "age" => 22);
60
Q6: How do you access an associative array value?
A: By its key, e.g. $arr["name"].
60
Q7: What is a multidimensional array?
A: An array containing other arrays.
61
Q8: How do you loop through an array?
A: Using a foreach loop.
62
Q9: Name two functions to sort an array?
A: sort() and rsort().
63
Q10: How do you count elements in an array?
A: Using count($array);.
64
Q1: What are PHP superglobals?
A: Predefined variables accessible from anywhere in code.
65
Q2: What does $_GET do?
A: Collects form data sent via URL.
66
Q3: What does $_POST do?
A: Collects form data submitted via POST method.
67
Q4: What does $_SERVER do?
A: Holds server and execution environment information.
68
Q5: What does $_SESSION store?
A: User session data across pages.
69
Q6: What does $_COOKIE store?
A: Stores small pieces of data on the user's device.
70
Q7: What does $_FILES handle?
A: File uploads in forms.
71
Q8: What does $_REQUEST do?
A: Collects data from both GET and POST requests.
72
Q9: How do you check if a form field is set?
A: Using isset($_POST['fieldname']);.
73
Q10: What does $_GLOBALS store?
A: All global variables in an array.
74
Q1: Why is form validation important?
A: To protect against spam and security threats.
75
Q2: What function removes whitespace from input?
A: trim().
76
Q3: What function removes backslashes from input?
A: trim().
77
Q3: What function removes backslashes from input?
A: stripslashes().
78
Q5: How do you check if a field is empty?
A: Using empty().
79
Q4: What function converts special characters?
A: htmlspecialchars().
80
Q6: How do you validate an email in PHP?
A: Using filter_var($email, FILTER_VALIDATE_EMAIL).
81
Q7: What is cross-site scripting (XSS)?
A: A security attack where attackers inject scripts into web forms.
82
Q8: How can PHP prevent XSS attacks?
A: By sanitizing input with htmlspecialchars().
83
Q9: What function filters input data?
A: filter_input().
84
Q10: How do you handle errors in form validation?
A: By checking conditions and showing error messages.
85
Q1: What is a cookie in PHP?
A: A small file stored on the user's computer.
86
Q2: How do you set a cookie in PHP?
A: Using setcookie(name, value, expiry);.
87
Q3: How do you access a cookie?
A: Using $_COOKIE['name'];.
88
Q4: How do you delete a cookie?
A: Set an expired time with setcookie(name, "", time() - 3600);.
89
Q5: What is a session in PHP?
A: A way to store user data across multiple pages.
90
Q6: How do you start a session?
A: Using session_start();.
91
Q7: How do you store session data?
A: Using $_SESSION['key'] = 'value';.
92
Q8: How do you remove session data?
A: Using unset($_SESSION['key']);.
93
Q9: How do you destroy an entire session?
A: Using session_destroy();.
94
Q10: What is the difference between a cookie and a session?
A: Cookies are stored on the client, sessions on the server.
95
Q1: What is MySQL?
A: A free, fast, and reliable database system.
96
Q2: How do you connect PHP to MySQL?
A: Using MySQLi or PDO extensions.
97
Q3: What does SQL stand for?
A: Structured Query Language.
98
Q4: How do you create a MySQL connection in PHP?
A: Using mysqli_connect(server, user, password, dbname);.
99
Q5: What function is used to close a MySQL connection?
A: mysqli_close($conn);.
100
Q6: How do you insert data into a MySQL table?
A: Using INSERT INTO table (columns) VALUES (values);.
101
Q7: How do you retrieve data from a MySQL table?
A: Using SELECT * FROM table;.
102
Q8: How do you update records in MySQL?
A: Using UPDATE table SET column=value WHERE condition;.
103
Q9: How do you delete records from MySQL?
A: Using DELETE FROM table WHERE condition;.
104
Q10: What function is used to execute SQL queries in PHP?
A: mysqli_query($conn, $query);.
105
Q1: What does MySQLi stand for?
A: MySQL Improved.
106
Q2: What is PDO?
A: PHP Data Objects, a database access layer.
107
Q3: Which extension works only with MySQL?
A: MySQLi.
108
Q4: Which extension supports multiple databases?
A: PDO.
109
Q5: Which is better for prepared statements, MySQLi or PDO?
A: Both support prepared statements.
110
Q6: What is an advantage of MySQLi?
A: Supports both procedural and object-oriented programming.
111
Q7: How do you connect to MySQL using PDO?
A: new PDO("mysql:host=host;dbname=db", "user", "password");.
112
Q8: Can you switch databases easily with PDO?
A: Yes, it supports 12+ databases.
113
Q9: Does MySQLi support exception handling?
A: No, but PDO does.
114
Q10: Which one is more secure, MySQLi or PDO?
A: Both are secure when using prepared statements.
115
Q1: What is a prepared statement?
A: A precompiled SQL statement to prevent SQL injection.
116
Q2: Why are prepared statements important?
A: They protect against SQL injection attacks.
117
Q3: How do you create a prepared statement in MySQLi?
A: Using $stmt = $conn->prepare("SQL query");.
118
Q4: How do you bind parameters in a prepared statement?
A: Using $stmt->bind_param("s", $var);.
119
Q5: What does the s in bind_param mean?
A: String; it defines the data type.
120
Q6: How do you execute a prepared statement?
A: Using $stmt->execute();.
121
Q7: How do you fetch results from a prepared statement?
A: Using $stmt->get_result();.
122
Q8: How do you close a prepared statement?
A: Using $stmt->close();.
123
Q9: What data types can be bound in prepared statements?
A: i (integer), d (double), s (string), b (blob).
124
Q10: What is an advantage of using prepared statements?
A: Faster execution and enhanced security.
