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) How do
you execute a PHP script from the command line.?
Just use the
PHP command line interface (CLI) and specify the file name of the script to be
executed as follows:
1
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php script.php
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Just use the
PHP CLI program with the option -a as follows:
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php -a
|
8 What are
the correct and the most two common way 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 ---] ?>
9) 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 ?>.
10) What is
the main difference between PHP 4 and PHP 5.?
PHP 5
presents many additional OOP (Object Oriented Programming) features.
11) Is
multiple inheritance 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’.
12) 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 overrided.
13) 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 ‘===’.
14) 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.
15) 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().
16) 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.
17) What is
needed to be able to use image function.?
GD library
is needed to be able execute image functions.
18) What is
the use of the function ‘imagetypes()’.?
imagetypes()
gives the image format and types supported by the current version of GD-PHP.
19) 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.
20) 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.
21) 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())
22) How can
I display text with a PHP script?
Two methods
are possible:
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2
3
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<?php
echo "Method
1";
print "Method
2";
?>
|
23) 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().
24) 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.
25)
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.
26) 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.
27) What is
the function file_get_contents() usefull for?
file_get_contents()
lets reading a file and storing it in a string variable.
28) 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:
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2
3
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<?php
$database =
mysql_connect("HOST", "USER_NAME", "PASSWORD");
mysql_select_db("DATABASE_NAME",$database);
?>
|
29) What is
the function mysql_pconnect() usefull for?
mysql_pconnect()
ensure a persistent connection to the database, it means that the connection do
not close when the the PHP script ends.
30) 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.
31) 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.
32) 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.
33) 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.
34) 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:
www.url.com?var=value
$variable = $_GET["var"]; this will now contain ‘value’
$variable = $_GET["var"]; this will now contain ‘value’
35) 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"];
36) 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.
37) 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.
38) 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.
39) What
does the unlink() function means?
The unlink()
function is dedicated for file system handling. It simply deletes the file
given as entry.
40) What
does the unset() function means?
The unlink()
function is dedicated for variable management. It will make a variable
undefined.
41) How do I
escape data before storing it into the database?
1
2
3
4
5
6
7
8
9
|
<?php
function testFunction()
{ static $testVariable
= 1;
echo $testVariable;
$testVariable++;
}
testFunction();
//1
testFunction();
//2
testFunction();
//3
?>
|
define
(“ACONSTANT”, 123);
54) How is
it possible to cast types in PHP?
The name of
the output type have to be specified in parentheses before the variable which
is to be cast as follows:
* (int),
(integer) – cast to integer
* (bool),
(boolean) – cast to boolean
* (float),
(double), (real) – cast to float
* (string) –
cast to string
* (array) –
cast to array
* (object) –
cast to object
Expression_1
? Expression_2 : Expression_3;
parent::constructor($value)
$variable1 =
‘Hello ‘;
$variable2 =
‘World’;
$variable3 =
$variable1.$variable2;
Or
2-
$variable3 = “$variable1$variable2″;
$variable3
will contain “Hello World”. The first code is faster than the second code
especially for large large sets of data.
A persistent
cookie is permanently stored in a cookie file on the browser’s computer. By
default, cookies are temporary and are erased if we close the browser.
Sessions
automatically ends when the PHP script finishs executing, but can be manually
ended using the session_write_close().
$_FILES['userfile']['name']
represents the original name of the file on the client machine,
$_FILES['userfile']['tmp_name']
represents the temporary filename of the file stored on the server.
74) How can
we get the error when there is a problem to upload a file?
$_FILES['userfile']['error']
contains the error code associated with the uploaded file.
$a &
$b: Bits that are set in both $a and
$b are set.
80) 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.
83) How can we determine whether a PHP variable is an instantiated object of a certain class?
The function
parse_ini_file() enables us to load in the ini file specified in filename, and
returns the settings in it in an associative array.
88) How can we
determine whether a variable is set?
The boolean
function isset determines if a variable is set and is not NULL.
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.
The function eregi_replace() is identical to the function ereg_replace() except that it ignores case distinction when matching alphabetic characters.
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