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Prepared By : Uday Shah (HOD-IT)
E-Mail : rupareleducation@gmail.com
Contact No : 7600044051
PHP SHORT
QUESTIONS
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1) What is PHP?
PHP is a web language based on scripts that allows
developers to dynamically create generated web pages.
2) What does the
initials of PHP stand for?
PHP means PHP: Hypertext Preprocessor.
3) Which programming
language does PHP resemble to?
PHP syntax resembles Perl and C
4) What does PEAR
stands for?
PEAR means “PHP Extension and Application Repository”. it
extends PHP and provides a higher level of programming for web developers.
5) What is the
actually used PHP version?
Version 5 is the actually used version of PHP.
6) What are the
correct and the most two common ways to start and finish a PHP block of code?
The two most common
ways to start and finish a PHP script are: <?php [ — PHP
code—- ] ?> and <? [— PHP
code —] ?>
7) How can we display
the output directly to the browser?
To be able to display the output directly to the browser, we
have to use the special tags <?= and ?>.
8) What is the main
difference between PHP 4 and PHP 5?
PHP 5 presents many additional OOP (Object Oriented
Programming) features.
9) Is multiple inheritances
supported in PHP?
PHP includes only single inheritance, it means that a class
can be extended from only one single class using the keyword ‘extended’.
10) What is the
meaning of a final class and a final method?
‘final’ is introduced in PHP5. Final class means that this
class cannot be extended and a final method cannot be override.
11) How comparison of
objects is done in PHP5?
We use the operator ‘==’ to test is two object are instanced
from the same class and have same attributes and equal values. We can test if
two object are refering to the same instance of the same class by the use of
the identity operator ‘===’.
12) How can PHP and
HTML interact?
It is possible to generate HTML through PHP scripts, and it
is possible to pass informations from HTML to PHP.
13) What type of
operation is needed when passing values through a form or an URL?
If we would like to pass values througn a form or an URL
then we need to encode and to decode them using htmlspecialchars() and
urlencode().
14) How can PHP and
Javascript interact?
PHP and Javascript cannot
directly interacts since PHP is a server side language and Javascript is a client
side language. However we can exchange variables since PHP is able to generate Javascript
code to be executed by the browser and it is possible to pass specific
variables back to PHP via the URL.
15) What is needed to
be able to use image function?
GD library is needed to be able execute image functions.
16) What is the use
of the function ‘imagetypes()’?
imagetypes() gives the image format and types supported by
the current version of GD-PHP.
17) What are the
functions to be used to get the image’s properties (size, width and height)?
The functions are getimagesize() for size, imagesx() for
width and imagesy() for height.
18) How failures in
execution are handled with include() and require() functions?
If the function require() cannot access to the file then it
ends with a fatal error. However, the include() function gives a warning and
the PHP script continues to execute.
19) What is the main
difference between require() and require_once()?
require() and require_once() perform the same task except
that the second function checks if the PHP script is already included or not
before executing it. (same for include_once() and include())
20) How can I display
text with a PHP script?
1 <!--?php echo "Method 1"; print "Method
2"; ?-->
21) How can we
display information of a variable and readable by human with PHP?
To be able to display a human-readable result we use
print_r().
22) How is it
possible to set an infinite execution time for PHP script?
The set_time_limit(0) added at
the beginning of a script sets to infinite the time of execution to not have the
PHP error ‘maximum execution time exceeded’.It is also possible to specify this
in the php.ini file.
23) What does the PHP
error ‘Parse error in PHP – unexpected T_variable at line x’ means?
This is a PHP syntax error expressing that a mistake at the
line x stops parsing and executing the
program.
24) What should we do
to be able to export data into an Excel file?
The most common and used way is to get data into a format
supported by Excel. For example, it is possible to write a .csv file, to choose
for example comma as separator between fields and then to open the file with
Excel.
25) What is the
function file_get_contents() usefull for?
file_get_contents() lets reading a file and storing it in a
string variable.
26) How can we
connect to a MySQL database from a PHP script?
To be able to connect to a MySQL database, we must use
mysql_connect() function as follows:
1
<!--?php $database = mysql_connect("HOST",
"USER_NAME", "PASSWORD");
mysql_select_db("DATABASE_NAME",$database);
?-->
27) What is the
function mysql_pconnect() usefull for?
mysql_pconnect() ensure a persistent connection to the
database, it means that the connection do no close when the the PHP script
ends.
28) How the result
set of Mysql be handled in PHP?
The result set can be handled using mysql_fetch_array,
mysql_fetch_assoc, mysql_fetch_object or mysql_fetch_row.
29) How is it
possible to know the number of rows returned in result set?
The function mysql_num_rows() returns the number of rows in
a result set.
30) Which function
gives us the number of affected entries by a query?
mysql_affected_rows() return the number of entries affected
by an SQL query.
31) What is the
difference between mysql_fetch_object() and mysql_fetch_array()?
The mysql_fetch_object() function collects the first single
matching record where mysql_fetch_array() collects all matching records from
the table in an array.
32) How can we access
the data sent through the URL with the GET method?
In order to access the data sent via the GET method, we you
use $_GET array like this:
$variable = $_GET[“var”]; this will now contain ‘value’
33) How can we access
the data sent through the URL with the POST method?
To access the data sent this way, you use the $_POST array.
Imagine you have a form field called ‘var’ on the form, when
the user clicks submit to the post form, you
can then access the value like this:
$_POST[“var”];
34) How can we check
the value of a given variable is a number?
It is possible to use the dedicated function, is_numeric()
to check whether it is a number or not.
35) How can we check
the value of a given variable is alphanumeric?
It is possible to use the dedicated function, ctype_alnum to
check whether it is an alphanumeric value or not.
36) How do I check if
a given variable is empty?
If we want to check whether a variable has a value or not,
it is possible to use the empty() function.
37) What does the
unlink() function means?
The unlink() function is dedicated for file system handling.
It simply deletes the file given as entry.
38) What does the
unset() function means?
The unset() function is dedicated for variable management.
It will make a variable undefined.
39) How do I escape
data before storing it into the database?
addslashes function enables us to escape data before storage
into the database.
40) How is it
possible to remove escape characters from a string?
The stripslashes function enables us to remove the escape
characters before apostrophes in a string.
41) How can we
automatically escape incoming data?
We have to enable the Magic quotes entry in the
configuration file of PHP.
42) What does the
function get_magic_quotes_gpc() means?
The function get_magic_quotes_gpc() tells us whether the
magic quotes is switched on or no.
43) Is it possible to
remove the HTML tags from data?
The strip_tags() function enables us to clean a string from
the HTML tags.
44) How can we define
a variable accessible in functions of a PHP script?
This feature is possible using the global keyword.
45) How is it possible
to return a value from a function?
A function returns a value using the instruction ‘return
$value;’.
46) What is the most
convenient hashing method to be used to hash passwords?
It is preferable to use crypt() which natively supports
several hashing algorithms or the function hash() which supports more variants
than crypt() rather than using the common hashing algorithms such as md5, sha1
or sha256 because they are conceived to be fast. hence, hashing passwords with
these algorithms can vulnerability.
47) Which
cryptographic extension provide generation and verification of digital
signatures?
The PHP-openssl extension
provides several cryptographic operations including generation and verification
of digital signatures.
48) How a constant is
defined in a PHP script?
The define() directive lets us defining a constant as
follows:
define (“ACONSTANT”, 123);
49) How is the
ternary conditional operator used in PHP?
It is composed of three expressions: a condition, and two
operands describing what instruction should be
performed when the specified condition is true or false as
follows:
Expression_1 ? Expression_2 : Expression_3;
50) What is the
function func_num_args() used for?
The function func_num_args() is used to give the number of
parameters passed into a function.
51) If the variable $var1 is set to 10 and the $var2 is set
to the character var1, what’s the value of $
$var2?
$$var2
contains the value 10.
52) In PHP, objects
are they passed by value or by reference?
In PHP, objects passed by value.
53) what is the
definition of a session?
A session is a logical object enabling us to preserve
temporary data across multiple PHP pages.
54) How to initiate a
session in PHP?
The use of the function session_start() lets us activating a
session.
55) When sessions ends?
Sessions automatically ends when
the PHP script finish executing, but can be manually ended using the session_write_close().
56) What does
$GLOBALS means?
$GLOBALS is associative array
including references to all variables which are currently defined in the global
scope of the script.
57) What does
$_SERVER means?
$_SERVER is an array including
information created by the web server such as paths, headers, and script locations.
58) What does
$_COOKIE means?
$_COOKIE is an associative array
of variables sent to the current PHP script using the HTTP Cookies.
59) What does the
scope of variables means?
The scope of a variable is the
context within which it is defined. For the most part all PHP variables only have
a single scope. This single scope spans included and required files as well.
60) What are the two
main string operators?
The first is the concatenation
operator (‘.’), which returns the concatenation of its right and left
arguments. The second is (‘.=’), which appends the argument on the right to the
argument on the left.
61) What does the
array operator ‘===’ means?
$a === $b TRUE if $a and $b have the same key/value pairs in
the same order and of the same types.
62) What is the
differences between $a != $b and $a !== $b?
!= means inequality (TRUE if $a is not equal to $b) and !==
means non-identity (TRUE if $a is not identical to $b).
63) How can we
determine whether a PHP variable is an instantiated object of a certain class?
To be able to verify whether a PHP variable is an
instantiated object of a certain class we use instanceof.
64) How can we
determine whether a variable is set?
The boolean function isset determines if a variable is set
and is not NULL.
65) What is the
difference between the functions strstr() and stristr()?
The string function strstr(string allString, string occ)
returns part of allString from the first occurrence of occ to the end of
allString. This function is case-sensitive. stristr() is identical to strstr()
except that it is case insensitive.
66) what is the
difference between for and foreach?
for is expressed as follows:
for (expr1; expr2; expr3)
statement
The first expression is executed once at the beginning. In
each iteration, expr2 is evaluated. If it is TRUE, the loop continues and the
statements inside for are executed. If it evaluates to FALSE, the execution of the
loop ends. expr3 is tested at the end of each iteration.
However, foreach provides an easy way to iterate over arrays
and it is only used with arrays and objects.
67) Is it possible to
submit a form with a dedicated button?
It is possible to use the document.form.submit() function to
submit the form. For example: <input
type=button value=”SUBMIT”
onClick=”document.form.submit()”>
68) What is the difference between ereg_replace() and eregi_replace()?
The function eregi_replace() is identical to the function
ereg_replace() except that it ignores case
distinction when matching alphabetic characters.
69) Is it possible to
destroy a cookie?
Yes, it is possible by setting the cookie with a past expiration
time.
70) What is the
default session time in php?
The default session time in php is until closing of browser
Differences between GET, POST and REQUEST methods ?
GET and POST are used to send information from client
browser to web server. In case of GET the information is send
via GET method in name/value pair and is URL encoded. The
default GET has a limit of 512 characters. The POST
method transfers the information via HTTP Headers. The POST
method does not have any restriction in data size to be
sent. POST is used for sending data securely and ASCII and
binary type’s data. The $_REQUEST contains the content of
both $_GET, $_POST and $_COOKIE.
71) What is session
and why do we use it?
Session is a super global variable that preserve data across
subsequent pages. Session uniquely defines each user with
a session ID, so it helps making customized web application
where user tracking is needed.
72) What is cookie
and why do we use it?
Cookie is a small piece of information stored in client
browser. It is a technique used to identify a user using the
information stored in their browser (if already visited that
website) . Using PHP we can both set and get COOKIE.
73) What is AJAX?
AJAX (Asynchronous JavaScript and XML) is a technique which
allows updating parts of a web page, without reloading
the whole page. Data is exchanged asynchronously in small
amounts of data with the server.
74) What is jQuery?
jQuery is a fast, small, and feature-rich JavaScript
library. It is an easy-to-use API which makes things like HTML
document traversal and manipulation, event handling,
animation, and Ajax much simpler across a multitude of browsers.
75) What is the
latest current version of PHP?
php 5.3
76) What are the
differences between GET and POST methods in form submitting?
On the server side, the main difference between GET and POST
is where the submitted is stored.
The $_GET array stores data submitted by the GET method. The
$_POST array stores data
submitted by the POST method.
On the browser side, the difference is that data submitted
by the GET method will be displayed in the
browser’s address field. Data submitted by the POST method
will not be displayed anywhere on the
browser.
GET method is mostly used for submitting a small amount and
less sensitive data.
POST method is mostly used for submitting a large amount or
sensitive data.
77) What are the
differences between require and include?
Both include and require used to include a file but when
included file not found
Include send Warning where as Require send Fatal Error .
78) How can we get
second of the current time using date function?
$second = date("s");
79) What is meant by
nl2br()?
Inserts HTML line breaks () before all newlines in a string.
80) What is use of
header() function in php ? What is the limitation of HEADER()?
In PHP Important to notice the Limitation of HEADER()
function is that header() must be called before any actual output is send.
Means must use header function before HTML or any echo statement
81) What is the
maximum length of a table name, a database name, or a field name in MySQL?
Database name: 64 characters
Table name: 64 characters
Column name: 64 characters
82)what types of
loops exist in php?
for,while,do while and foreach
83)How to create a
mysql connection?
mysql_connect(servername,username,password);
84)How to select a
database?
mysql_select_db($db_name);
85)How to execute an
sql query? How to fetch its result ?
$my_qry = mysql_query("SELECT * FROM `users` WHERE
`u_id`='1'; ");
$result = mysql_fetch_array($my_qry);
echo $result['First_name'];
86)How we can
retrieve the data in the result set of MySQL using PHP?
1. mysql_fetch_row
2. mysql_fetch_array
3. mysql_fetch_object
4. mysql_fetch_assoc
87)What is the use of
explode() function ?
Syntax : array explode ( string $delimiter , string $string
[, int $limit ] );
This function breaks a string into an array. Each of the
array elements is a substring of string formed
by splitting it on boundaries formed by the string
delimiter.
88)What is the
difference between mysql_fetch_array() and mysql_fetch_assoc() ?
mysql_fetch_assoc() function
Fetch a result row as an associative array, While mysql_fetch_array() fetches
an associative array, a numeric array, or both
89)What is the
importance of "action" attribute in a html form?
The action attribute determines where to send the form-data
in the formsubmission.
90)How send email
using php?
To send email using PHP, you use the mail() function.This
mail() function accepts 5 parameters as follows (the last 2 are optional). You
need webserver, you can't send email from localhost.
eg :
mail($to,$subject,$message,$headers);
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