1. Described PHP?

The PHP Hypertext Preprocessor is a programming language that allows web developers to create dynamic content that interacts with databases. PHP is basically used for developing web based software applications.

2. Described session in PHP?

A session is a logical object created by the PHP engine to allow you to preserve data across subsequent HTTP requests.

There is only one session object available to your PHP scripts at any time. Data saved to the session by a script can be retrieved by the same script or another script when requested from the same visitor.

Sessions are commonly used to store temporary data to allow multiple PHP pages to offer a complete functional transaction for the same visitor.

3. What is PEAR in PHP?

PEAR is the next revolution in PHP. This repository is bringing higher level programming to PHP. PEAR is a framework and distribution system for reusable PHP components. It eases installation by bringing an automated wizard, and packing the strength and experience of PHP users into a nicely organised OOP library. PEAR also provides a command-line interface that can be used to automatically install "packages"

4. Can you please explain the difference between $message and $$message?

They are both variables. But $message is a variable with a fixed name. $$message is a variable who's name is stored in $message. For example, if $message contains "var", $$message is the same as $var.

$message is a simple variable whereas $$message is a reference variable. Example:
$user = 'bob'
is equivalent to
$holder = 'user';
$$holder = 'bob';

5. How you can protect special characters in Query String?

If you want to include special characters like spaces in the query string, you need to protect them by applying the urlencode() translation function. The script below shows how to use urlencode():

<?php
print("<html>");
print("<p>Please click the links below"
." to submit comments about GlobalGuideLine.com:</p>");
$comment = 'I want to say: "It's a good site! :->"';
$comment = urlencode($comment);
print("<p>"
."<a href="processing_forms.php?name=Guest&comment=$comment">"
."It's an excellent site!</a></p>");
$comment = 'This visitor said: "It's an average site! :-("';
$comment = urlencode($comment);
print("<p>"
.'<a href="processing_forms.php?'.$comment.'">'
."It's an average site.</a></p>");
print("</html>");
?>

6. Suppose if variable $a is equal to 5 and variable $b is equal to character a, what's the value of $$b?

100, it's a reference to existing variable.

7. List the purpose of the following files having extensions: frm, myd, and myi? What these files contain?

In MySQL, the default table type is MyISAM.
Each MyISAM table is stored on disk in three files. The files have names that begin with the table name and have an extension to indicate the file type.

The '.frm' file stores the table definition.
The data file has a '.MYD' (MYData) extension.
The index file has a '.MYI' (MYIndex) extension,

8. How to find out the number of parameters passed into function9.?

func_num_args() function returns the number of parameters passed in.

9. Can you please explain the difference between ereg_replace() and eregi_replace()?

eregi_replace() function is identical to ereg_replace() except that it ignores case distinction when matching alphabetic characters.

10. Described the functionality of the function strstr and stristr?

strstr() returns part of a given string from the first occurrence of a given substring to the end of the string. For example: strstr("user@example.com","@") will return "@example.com".
stristr() is idential to strstr() except that it is case insensitive.

Download Interview PDF

11. How to send mail using JavaScript?

No. There is no way to send emails directly using JavaScript.
But you can use JavaScript to execute a client side email program send the email using the "mailto" code. Here is an example:

function myfunction(form)
{
tdata=document.myform.tbox1.value;
location="mailto:mailid@domain.com?subject=...";
return true;
}

12. When you supposed to use endif to end the conditional statement?

When the original if was followed by : and then the code block without braces.

13. How to pass a variable by value?

Just like in C++, put an ampersand in front of it, like $a = &$b.

14. How to encrypt the username and password using PHP?

You can encrypt a password with the following Mysql>SET PASSWORD=PASSWORD("Password");
Or:
You can use the MySQL PASSWORD() function to encrypt username and password. For example,
INSERT into user (password, ...) VALUES (PASSWORD($password")), ...);

15. How to create table using PHP?

If you want to create a table, you can run the CREATE TABLE statement as shown in the following sample script:

<?php
include "mysql_connection.php";
$sql = "CREATE TABLE ggl_links ("
. " id INTEGER NOT NULL"
. ", url VARCHAR(80) NOT NULL"
. ", notes VARCHAR(1024)"
. ", counts INTEGER"
. ", time TIMESTAMP DEFAULT sysdate()"
. ")";
if (mysql_query($sql, $con)) {
print("Table ggl_links created.n");
} else {
print("Table creation failed.n");
}

mysql_close($con);
?>
Remember that mysql_query() returns TRUE/FALSE on CREATE statements. If you run this script, you will get something like this:
Table ggl_links created.

16. List the different tables present in MySQL?

Total 5 types of tables we can create:
1) MyISAM
2) Heap
3) Merge
4) INNO DB
5) ISAM

17. Can I use print "$a dollars" or "{$a} dollars" to print out the amount of dollars in this example?

In this example it wouldn't matter, since the variable is all by itself, but if you were to print something like "{$a},000,000 mln dollars", then you definitely need to use the braces.

18. I am trying to assign variable the value of 0123, but it keeps coming up with a different number, what is the problem?

PHP Interpreter treats numbers beginning with 0 as octal. Look at the similar PHP interview questions for more numeric problems.

19. How to execute a PHP script using command line?

Just run the PHP CLI (Command Line Interface) program and provide the PHP script file name as the command line argument. For example, "php myScript.php", assuming "php" is the command to invoke the CLI program.
Be aware that if your PHP script was written for the Web CGI interface, it may not execute properly in command line environment.

20. Can you please explain the difference between mysql_fetch_object and mysql_fetch_array?

MySQL fetch object will collect first single matching record where mysql_fetch_array will collect all matching records from the table in an array.

21. How to get uploaded file information in the Receiving Script?

Once the Web server received the uploaded file, it will call the PHP script specified in the form action attribute to process them. This receiving PHP script can get the uploaded file information through the predefined array called $_FILES. Uploaded file information is organized in $_FILES as a two-dimensional array as:

* $_FILES[$fieldName]['name'] - The Original file name on the browser system.
* $_FILES[$fieldName]['type'] - The file type determined by the browser.
* $_FILES[$fieldName]['size'] - The Number of bytes of the file content.
* $_FILES[$fieldName]['tmp_name'] - The temporary filename of the file in which the uploaded file was stored on the server.
* $_FILES[$fieldName]['error'] - The error code associated with this file upload.

The $fieldName is the name used in the <INPUT TYPE=FILE, NAME=fieldName>.

22. Define urlencode and urldecode?

urlencode() returns the URL encoded version of the given string. URL coding converts special characters into % signs followed by two hex digits. For example: urlencode("10.00%") will return "10%2E00%25". URL encoded strings are safe to be used as part of URLs.
urldecode() returns the URL decoded version of the given string.

string urlencode(str) - Returns the URL encoded version of the input string. String values to be used in URL query string need to be URL encoded. In the URL encoded version:

Alphanumeric characters are maintained as is.
Space characters are converted to "+" characters.
Other non-alphanumeric characters are converted "%" followed by two hex digits representing the converted character.
string urldecode(str) - Returns the original string of the input URL encoded string.

For example:
$discount ="10.00%";
$url = "http://domain.com/submit.php?disc=".urlencode($discount);
echo $url;
You will get "http://domain.com/submit.php?disc=10%2E00%25".

23. Can you please explain the difference between require and include, include_once?

require_once() and include_once() are both the functions to include and evaluate the specified file only once. If the specified file is included previous to the present call occurrence, it will not be done again.
But require() and include() will do it as many times they are asked to do.

The include_once() statement includes and evaluates the specified file during the execution of the script. This is a behavior similar to the include() statement, with the only difference being that if the code from a file has already been included, it will not be included again. The major difference between include() and require() is that in failure include() produces a warning message whereas require() produces a fatal errors.

24. Write the FORM Tag correctly for uploading files?

When users clicks the submit button, files specified in the <INPUT TYPE=FILE...> will be transferred from the browser to the Web server. This transferring (uploading) process is controlled by a properly written <FORM...> tag as:

<FORM ACTION=receiving.php METHOD=post ENCTYPE=multipart/form-data>

Note that you must specify METHOD as "post" and ENCTYPE as "multipart/form-data" in order for the uploading process to work. The following PHP code, called logo_upload.php, shows you a complete FORM tag for file uploading:

<?php
print("<html><form action=processing_uploaded_files.php"
." method=post enctype=multipart/form-data>n");
print("Please submit an image file a Web site logo for"
." globalguideline.com:
n");
print("<input type=file name=globalguideline_logo>
n");
print("<input type=submit>n");
print("</form></html>n");
?>

25. Define constant in PHP?

Via define() directive, like define ("MYCONSTANT", 100);

Download Interview PDF

26. What does special set of tags do in PHP?

What does a special set of tags <?= and ?> do in PHP?
The output is displayed directly to the browser.

27. Described persistent cookie in PHP?

A persistent cookie is a cookie which is stored in a cookie file permanently on the browser's computer. By default, cookies are created as temporary cookies which stored only in the browser's memory. When the browser is closed, temporary cookies will be erased. You should decide when to use temporary cookies and when to use persistent cookies based on their differences:

► Temporary cookies can not be used for tracking long-term information.
► Persistent cookies can be used for tracking long-term information.
► Temporary cookies are safer because no programs other than the browser can access them.
► Persistent cookies are less secure because users can open cookie files see the cookie values.

28. How to repair MySQL table?

The syntex for repairing a mysql table is:

REPAIR TABLE tablename
REPAIR TABLE tablename QUICK
REPAIR TABLE tablename EXTENDED

This command will repair the table specified.
If QUICK is given, MySQL will do a repair of only the index tree.
If EXTENDED is given, it will create index row by row.

29. How to know the number of days between two given dates using PHP?

Simple arithmetic:
$date1 = date('Y-m-d');
$date2 = '2006-07-01';
$days = (strtotime() - strtotime()) / (60 * 60 * 24);
echo "Number of days since '2006-07-01': $days";

30. Where PHP configuration settings stored?

PHP stores configuration settings in a file called php.ini in PHP home directory. You can open it with any text editor to your settings.

31. How to replace substring in a given string in PHP?

If you know the position of a substring in a given string, you can replace that substring by another string by using the substr_replace() function. Here is a PHP script on how to use substr_replace():

<?php
$string = "Warning: System will shutdown in NN minutes!";
$pos = strpos($string, "NN");
print(substr_replace($string, "15", $pos, 2)." ");
sleep(10*60);
print(substr_replace($string, "5", $pos, 2)." ");
?>

This script will print:
Warning: System will shutdown in 15 minutes!
(10 minutes later)
Warning: System will shutdown in 5 minutes!
Like substr(), substr_replace() can take negative starting position counted from the end of the string.

32. How you take a substring from a given string in PHP?

If you know the position of a substring in a given string, you can take the substring out by the substr() function. Here is a PHP script on how to use substr():

<?php
$string = "beginning";
print("Position counted from left: ".substr($string,0,5)." ");
print("Position counted form right: ".substr($string,-7,3)." ");
?>

This script will print:
Position counted from left: begin
Position counted form right: gin
substr() can take negative starting position counted from the end of the string.

33. Which is the best way to test the strpos() Return Value in PHP?

Because strpos() could two types of values, Integer and Boolean, you need to be careful about testing the return value. The best way is to use the "Identical(===)" operator. Do not use the "Equal(==)" operator, because it does not differentiate "0" and "false". Check out this PHP script on how to use strpos():

<?php
$haystack = "needle234953413434516504381640386488129";
$pos = strpos($haystack, "needle");
if ($pos==false) {
print("Not found based (==) test ");
} else {
print("Found based (==) test ");
}
if ($pos===false) {
print("Not found based (===) test ");
} else {
print("Found based (===) test ");
}
?>

This script will print:
Not found based (==) test
Found based (===) test
Of course, (===) test is correct.

34. How you find a substring from a given string in PHP?

To find a substring in a given string, you can use the strpos() function. If you call strpos($haystack, $needle), it will try to find the position of the first occurrence of the $needle string in the $haystack string. If found, it will return a non-negative integer represents the position of $needle. Othewise, it will return a Boolean false. Here is a PHP script example of strpos():

<?php
$haystack1 = "2349534134345globalguideline16504381640386488129";
$haystack2 = "globalguideline234953413434516504381640386488129";
$haystack3 = "guideline234953413434516504381640386488129ggl";
$pos1 = strpos($haystack1, "globalguideline");
$pos2 = strpos($haystack2, "globalguideline");
$pos3 = strpos($haystack3, "globalguideline");
print("pos1 = ($pos1); type is " . gettype($pos1) . " ");
print("pos2 = ($pos2); type is " . gettype($pos2) . " ");
print("pos3 = ($pos3); type is " . gettype($pos3) . " ");
?>

This script will print:
pos1 = (13); type is integer
pos2 = (0); type is integer
pos3 = (); type is boolean
"pos3" shows strpos() can return a Boolean value

35. How to get number of characters in a String?

You can use the "strlen()" function to get the number of characters in a string. Here is a PHP script example of strlen():
<?php
print(strlen('It's Friday!'));
?>
This script will print:
12

36. How you can remove leading and trailing spaces from user input values in PHP?

If you are taking input values from users with a Web form, users may enter extra spaces at the beginning and/or the end of the input values. You should always use the trim() function to remove those extra spaces as shown in this PHP script:

<?php
$name = $_REQUEST("name");
$name = trim($name);
# $name is ready to be used...
?>

37. How you can remove the new line character from the end of a text line in PHP?

If you are using fgets() to read a line from a text file, you may want to use the chop() function to remove the new line character from the end of the line as shown in this PHP script:

<?php
$handle = fopen("/tmp/inputfile.txt", "r");
while ($line=fgets()) {
$line = chop($line);
# process $line here...
}
fclose($handle);
?>

38. How you can remove white spaces from the beginning and/or the end of a String in PHP?

There are 4 PHP functions you can use remove white space characters from the beginning and/or the end of a string:

► trim() - Remove white space characters from the beginning and the end of a string.
► ltrim() - Remove white space characters from the beginning of a string.
► rtrim() - Remove white space characters from the end of a string.
► chop() - Same as rtrim().

White space characters are defined as:
► " " (ASCII 32 (0x20)), an ordinary space.
► " " (ASCII 9 (0x09)), a tab.
► " " (ASCII 10 (0x0A)), a new line (line feed).
► " " (ASCII 13 (0x0D)), a carriage return.
► "

39. How to convert the strings to numbers in PHP?

In a numeric context, PHP will automatically convert any string to a numeric value. Strings will be converted into two types of numeric values, double floating number and integer, based on the following rules:

► The value is given by the initial portion of the string. If the string starts with valid numeric data, this will be the value used. Otherwise, the value will be 0 (zero).
► If the valid numeric data contains '.', 'e', or 'E', it will be converted to a double floating number. Otherwise, it will be converted to an integer.

40. How to convert the numbers to strings in PHP?

In a string context, PHP will automatically convert any numeric value to a string. Here is a PHP script examples:

<?php
print(-1.3e3);
print(" ");
print(strlen(-1.3e3));
print(" ");
print("Price = $" . 99.99 . " ");
print(1 . " + " . 2 . " = " . 1+2 . " ");
print(1 . " + " . 2 . " = " . (1+2) . " ");
print(1 . " + " . 2 . " = 3 ");
print(" ");
?>

This script will print:

-1300
5
Price = $99.99
3
1 + 2 = 3
1 + 2 = 3

The print() function requires a string, so numeric value -1.3e3 is automatically converted to a string "-1300". The concatenation operator (.) also requires a string, so numeric value 99.99 is automatically converted to a string "99.99". Expression (1 . " + " . 2 . " = " . 1+2 . " ") is a little bit interesting. The result is "3 " because concatenation operations and addition operation are carried out from left to right. So when the addition operation is reached, we have "1 + 2 = 1"+2, which will cause the string to be converted to a value 1.

Download Interview PDF

41. How to compare the two strings with Comparison Operators in PHP?

PHP supports 3 string comparison operators, <, ==, and >, that generates Boolean values. Those operators use ASCII values of characters from both strings to determine the comparison results. Here is a PHP script on how to use comparison operators:

<?php
$a = "PHP is a scripting language.";
$b = "PHP is a general-purpose language.";
if ($a > $b) {
print('$a > $b is true.'." ");
} else {
print('$a > $b is false.'." ");
}
if ($a == $b) {
print('$a == $b is true.'." ");
} else {
print('$a == $b is false.'." ");
}
if ($a < $b) {
print('$a < $b is true.'." ");
} else {
print('$a < $b is false.'." ");
}
?>

This script will print:
$a > $b is true.
$a == $b is false.
$a < $b is false.

42. How To concatenate the two strings together in PHP?

You can use the string concatenation operator (.) to join two strings into one. Here is a PHP script example of string concatenation:

<?php
echo 'Hello ' . "world! ";
?>
This script will print:
Hello world!

43. How you can assign a new character in a String using PHP?

The string element expression, $string{index}, can also be used at the left side of an assignment statement. This allows you to assign a new character to any position in a string. Here is a PHP script example:

<?php
$string = 'It's Friday?';
echo "$string ";
$string{11} = '!';
echo "$string ";
?>

This script will print:
It's Friday?
It's Friday!

44. How To get access a specific character in a String using PHP?

Any character in a string can be accessed by a special string element expression:
► $string{index} - The index is the position of the character counted from left and starting from 0.

Here is a PHP script example:
<?php
$string = 'It's Friday!';
echo "The first character is $string{0} ";
echo "The first character is {$string{0}} ";
?>

This script will print:
The first character is It's Friday!{0}
The first character is I

45. How many ways to include the array elements in Double-Quoted Strings using PHP?

There are 2 formats to include array elements in double-quoted strings in PHP:

► "part 1 $array[key] part 2" - This is called simple format. In this format, you can not specify the element key in quotes.
► "part 1 {$array['key']} part 2" - This is called complex format. In this format, the array element expression is specified in the same way as in a normal statement.

Here is a PHP script example of different ways to include variables in double-quoted strings:
<?php
$fruits = array('strawberry' => 'red', 'banana' => 'yellow');
echo "A banana is $fruits[banana]. ";
echo "A banana is {$fruits['banana']}. ";
?>

This script will print:
A banana is yellow.
A banana is yellow.
"A banana is $fruits['banana']. " will give you a syntax error.

46. How many ways to include the variables in Double-Quoted Strings in PHP?

There are 3 formats to include variables in double-quoted strings:

► "part 1 $variable part 2" - This is the simplest format to include a variable in a string. The variable name starts with the dollar sign and ends at the first character that can not be used in variable name. Space is good character to end a variable name.
► "part 1${variable}part 2" - This format helps you to clearly end the variable name. The variable name starts at dollar sign before the open brace (${) and ends at the close brace (}).
► "part 1{$variable}part 2" - This format is also called complex format. You use this format to specify any complex variable expression in the same way as in a normal statement. The variable expression starts at ({$) followed by a variable name and ends at (}).

Here is a PHP script example of different ways to include variables in double-quoted strings:
<?php
$beer = 'Heineken';
echo "$beer's taste is great. ";
echo "He drank some ${beer}s and water. ";
echo "She drank some {$beer}s and water. ";
?>

This script will print:
Heineken's taste is great.
He drank some Heinekens and water.
She drank some Heinekens and water.

47. How you can include variables in Double-Quoted Strings in PHP?

Variables included in double-quoted strings will be interpolated. Their values will be concatenated into the enclosing strings. For example, two statements in the following PHP script will print out the same string:
<?php
$variable = "and";
echo "part 1 $variable part 2 ";
echo "part 1 ".$variable." part 2 ";
?>

This script will print:
part 1 and part 2
part 1 and part 2

48. Tell me how many escape sequences are recognized in Double-Quoted Strings in PHP?

There are 12 escape sequences you can use in double-quoted strings:
► - Represents the back slash character.
► " - Represents the double quote character.
► $ - Represents the dollar sign.
► - Represents the new line character (ASCII code 10).
► - Represents the carriage return character (ASCII code 13).
► - Represents the tab character (ASCII code 9).
► { - Represents the open brace character.
► } - Represents the close brace character.
► [ - Represents the open bracket character.
► ] - Represents the close bracket character.
► nn - Represents a character as an octal value.
► xnn - Represents a character as a hex value.

49. Which special characters need to escape in Double-Quoted Stings?

There are two special characters you need to escape in a double-quote string: the double quote (") and the back slash (). Here is a PHP script example of double-quoted strings:

<?php
echo "Hello world!";
echo "Tom said: "Who's there?"";
echo " represents an operator.";
?>
This script will print:
Hello world!Tom said: "Who's there?" represents an operator.

50. How to specify the "new line" character in Single-Quoted Strings?

You can not specify the "new line" character in a single-quoted string. If you don't believe, try this script:
<?php
echo ' will not work in single quoted strings.';
?>

This script will print:
will not work in single quoted strings.
How Many Escape Sequences Are Recognized in Single-Quoted Strings?

There are 2 escape sequences you can use in single-quoted strings:
► - Represents the back slash character.
► ' - Represents the single quote character.

51. Which special characters need to escape in Single-Quoted Stings?

There are two special characters you need to escape in a single-quote string: the single quote (') and the back slash (). Here is a PHP script example of single-quoted strings:

<?php
echo 'Hello world!';
echo 'It's Friday!';
echo ' represents an operator.';
?>
This script will print:
Hello world!It's Friday! represents an operator.

Answer #2
echo 'hi how are you';
echo ' it's free of cost';
echo 'end of the program';
?>
This script will print

52. How you can Run a PHP Script?

A standard alone PHP script can be executed directly with the PHP Command Line Interface (CLI). Write the following script in a file called hello.php:

<?php echo "Hello world!"; ?>
This script can be executed by CLI interface like this:
phpphp hello.php
You should see the "Hello world!" message printed on your screen.

53. How I can download and Install PHP for Windows?

The best way to download and install PHP on Windows systems is to:

► Go to http://www.php.net, which is the official Web site for PHP.
► Download PHP binary version for Windows in ZIP format.
► Unzip the downloaded file into a directory.
You are done. No need to run any install program.

54. How to check PHP Installation?

PHP provides two execution interfaces: Command Line Interface (CLI) and Common Gateway Interface (CGI). If PHP is installed in the php directory on your system, you can try this to check your installation:

* Run "phpphp -v" command to check the Command Line Interface (CLI).
* Run "phpphp-cgi -v" command to check the Common Gateway Interface (CGI).

If you see PHP printing the version information on your screen for both commands, your installation is ok. Open a command window and run the commands below:

C:>phpphp -v
PHP 5.2.2 (cli) (built: May 2 2007 19:18:26)
Copyright (c) 1997-2007 The PHP Group
Zend Engine v2.2.0 Copyright (c) 1998-2007 Zend Technologies

C:>phpphp-cgi -v
PHP 5.2.2 (cgi-fcgi) (built: May 2 2007 19:18:25)
Copyright (c) 1997-2007 The PHP Group
Zend Engine v2.2.0 Copyright (c) 1998-2007 Zend Technologies

55. How I can download and Install PHP on Windows?

PHP is one of the most popular languages to develop dynamic Web pages. It supports all major database servers, including: MySQL, MS SQL Server, Oracle, mSQL, Sybase, etc.

If you are developing a Web application that uses PHP and needs to access MS SQL Server, you should go download and install PHP to your local machine to practice PHP and SQL Server connection. The best way to download and install PHP on Windows systems is to:

* Go to http://www.php.net, which is the official Web site for PHP.
* Click the Downloads menu link. You will see the PHP download page.
* Go to the "Windows Binaries" section, and click "PHP 5.2.3 zip package" link to download PHP binary version for Windows in ZIP format.
* Save the downloaded file, php-5.2.3-Win32.zip with 9,847,499 bytes, in C:Temp directory.
* Unzip the downloaded file into directory C:php.
You are done. No need to run any installation program.

Download Interview PDF