PHP Interview Quesition & Answer2

16.What is the difference between Notify URL and Return URL?

Notify URL and Return URL is used in Paypal Payment Gateway integration. Notify URL is used by PayPal to post information about the transaction. Return URL is sued by the browser; A url where the user needs to be redirected on completion of the payment process.

17.Describe functions STRSTR() and STRISTR.

Both the functions are used to find the first occurrence of a string. Parameters includes: input String, string whose occurrence needs to be found, TRUE or FALSE (If TRUE, the functions return the string before the first occurrence.
STRISTR is similar to STRSTR. However, it is case-insensitive
E.g. strstr ($input_string, string)

18.What are the different types of errors in PHP?

  • E_ERROR: A fatal error that causes script termination
  • E_WARNING: Run-time warning that does not cause script termination
  • E_PARSE: Compile time parse error.
  • E_NOTICE: Run time notice caused due to error in code
  • E_CORE_ERROR: Fatal errors that occur during PHP’s initial startup (installation)
  • E_CORE_WARNING: Warnings that occur during PHP’s initial startup
  • E_COMPILE_ERROR: Fatal compile-time errors indication problem with script.
  • E_USER_ERROR: User-generated error message.
  • E_USER_WARNING: User-generated warning message.
  • E_USER_NOTICE: User-generated notice message.
  • .E_STRICT: Run-time notices.
  • E_RECOVERABLE_ERROR: Catchable fatal error indicating a dangerous error
  • E_ALL: Catches all errors and warnings

19.What are the different types of Errors in PHP?

There are three basic types of runtime errors in PHP:

1. Notices: These are small, non-critical errors that PHP encounters while executing a script – for example, accessing a variable that has not yet been defined. By default, such errors are not displayed to the user at all – although the default behavior can be changed.

2. Warnings: Warnings are more severe errors like attempting to include() a file which does not exist. By default, these errors are displayed to the user, but they do not result in script termination.

3. Fatal errors: These are critical errors – for example, instantiating an object of a non-existent class, or calling a non-existent function. These errors cause the immediate termination of the script, and PHP’s default behavior is to display them to the user when they take place.

20.How can we know the number of days between two given dates using PHP?

The start date and end date can be first found as shown below:

$date1= strotime($start_date);
$date2= strotime($end_date);
$date_diff = (($date1)- ($date2)) / (60*60*24)

21.How to connect PHP wil MySQL?

<?
mysql_connect(‘db.domain.com:33306′,’root’,’user’);
mysql_connect(‘localhost:/tmp/mysql.sock’);
mysql_connect(‘localhost’,’rasmus’,’foobar’,
true,MYSQL_CLIENT_SSL|MYSQL_CLIENT_COMPRESS);
?>

22.HTTP headers can be used in PHP by redirection which is written as:

<?header(‘Location: http://www.php.net’)?>
The headers can be added to HTTP response in PHP using the header(). The response headers are sent before any actual response being sent. The HTTP headers have to be sent before taking the output of any data. The statement above gets included at the top of the script.

23.Why PHP is also called as Scripting language?

PHP is basically a general purpose language, which is used to write scripts. Scripts are normal computer files that consist of instructions written in PHP language. It tells the computer to execute the file and print the output on the screen. PHP is used for webpages and to create websites, thus included as scripting language.

24.Why many companies are switching their current business language to PHP? Where PHP basically used?

PHP is rapidly gaining the popularity and many companies are switching their current language for this language. PHP is a server side scripting language. PHP executes the instructions on the server itself. Server is a computer where the web site is located. PHP is used to create dynamic pages and provides faster execution of the instructions.

25.What is the use of PEAR in php?

PEAR is known as PHP Extension and Application Repository. It provides structured library to the PHP users and also gives provision for package maintenance.

26.What is the difference between PHP and JavaScript?

The difference lies with the execution of the languages. PHP is server side scripting language, which means that it can’t interact directly with the user. Whereas, JavaScript is client side scripting language, that is used to interact directly with the user

27.What does ODBC do in context with PHP?

PHP supports many databases like dBase, Microsft SQL Server, Oracle, etc. But, it also supports databases like filePro, FrontBase and InterBase with ODBC connectivity. ODBC stands for Open Database connectivity, which is a standard that allows user to communicate with other databases like Access and IBM DB2.

28.Why PHP is sometimes called as embedded scripting language?

PHP is a high level language which is used to allow users to write and understand it in human readable form and also use an interpreter to interpret the code which user write for the computer. PHP is used as an embedded scripting language for the web. PHP is embedded in HTML code. HTML tags are used to enclose the PHP language. HTML is used and PHP is code written in it in the same way as you write JavaScript in HTML.

29.What is the difference between echo, print and printf()?

Echo is the basic type used to print out a string. It just shows the content of the message written using it. It can have multiple parameters as well. print is a construct, it returns TRUE on successful output and FALSE there is no output. It can’t have multiple parameters. Printf() is a function, and not be used as a construct. It allows the string output to be formatted. It is the slowest medium to print the data out.

30.Why IDE is recommended for use while programming with PHP?

IDE stands for Integrated Development environment; it is a framework for developing applications. It includes programming editor where you can edit and write the development programs. The features of IDE are as follows:

  • 1. Debugging: this is the feature which is used to debug or find the bugs in a program.
  • 2. Preview: this is the feature which allow instant preview of the program you are writing.
  • 3. Testing: this is the features that includes built in testing features through which you can check your scripts.
  • 4. FTP: through this you can upload and download the file while connecting to the server.
  • 5. Project management: it organizes scripts into projects; manages the files in the project; includes file checkout and check-in features.
  • 6. Backups: it creates backups automatically of your Web site at periodic intervals.
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