Here are common questions with answer that every fresher PHP programmer is expected to know, I will add few more questions with answers in coming days.
Q- What is the difference between include and require
Difference between require() and include() is that require() produces a FATAL ERROR if the file you want to include is not found, while include() only produces a WARNING.
Q- What is the difference between Session and Cookie
Sessions are stored in the server side whereas cookies are stored in the client side.
Magic methods are the members functions that is available to all the instance of class Magic methods always starts with “__”. Eg. __construct All magic methods needs to be declared as public To use magic method they should be defined within the class or program scope Various Magic Methods used in PHP 5 are: __construct() __destruct() __set() __get() __call() __toString() __sleep() __wakeup() __isset() __unset() __autoload() __clone()
Q 2- What is magic quotes?
Ans:
Magic Quotes is a process that automagically escapes incoming data to the PHP script. It’s preferred to code with magic quotes off and to instead escape the data at runtime, as needed. This feature has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 6.0.0. Relying on this feature is highly discouraged.
Q 3- What is design pattern? singleton pattern?
Ans:
A design pattern is a general reusable solution to a commonly occurring problem in software design.
The Singleton design pattern allows many parts of a program to share a single resource without having to work out the details of the sharing themselves.
Q 4- Types of error? how to set error settings at run time?
Ans:
Here are three basic types of runtime errors in PHP:
i. Notices: These are trivial, 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 you can change this default behaviour.
ii. Warnings: These are more serious errors – for example, 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.
iii. 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 behaviour is to display them to the user when they take place.
Q 5- what is cross site scripting? SQL injection?
Ans:
Cross-site scripting (XSS) is a type of computer security vulnerability typically found in web applications which allow code injection by malicious web users into the web pages viewed by other users. Examples of such code include HTML code and client-side scripts.
SQL injection is a code injection technique that exploits a security vulnerability occurring in the database layer of an application. The vulnerability is present when user input is either incorrectly filtered for string literal escape characters embedded in SQL statements or user input is not strongly typed and thereby unexpectedly executed
Q 6- what is URL rewriting?
Ans:
Using URL rewriting we can convert dynamic URl to static URL. Static URLs are known to be better than Dynamic URLs because of a number of reasons
i. Static URLs typically Rank better in Search Engines. ii. Search Engines are known to index the content of dynamic pages a lot slower compared to static pages. iii. Static URLs are always more friendlier looking to the End Users.
Q 7- What is the major php security hole? how to avoid?
Ans:
a) Never include, require, or otherwise open a file with a filename based on user input, without thoroughly checking it first. b) Be careful with eval() Placing user-inputted values into the eval() function can be extremely dangerous. You essentially give the malicious user the ability to execute any command he or she wishes! c) Be careful when using register_globals = ON It was originally designed to make programming in PHP easier (and that it did), but misuse of it often led to security holes. d) Never run unescaped queries. e) For protected areas, use sessions or validate the login every time. f) If you don’t want the file contents to be seen, give the file a .php extension.
Q 8- What is MVC? why its been used?
Ans:
Model-view-controller (MVC) is an architectural pattern used in software engineering. Successful use of the pattern isolates business logic from user interface considerations, resulting in an application where it is easier to modify either the visual appearance of the application or the underlying business rules without affecting the other. In MVC, the model represents the information (the data) of the application; the view corresponds to elements of the user interface such as text, checkbox items, and so forth; and the controller manages the communication of data and the business rules used to manipulate the data to and from the model.
Q 9- What is framework? how it works? what is advantage?
Ans:
In general, a framework is a real or conceptual structure intended to serve as a support or guide for the building of something that expands the structure into something useful. Advantages : Consistent Programming Model Direct Support for Security Simplified Development Efforts Easy Application Deployment and Maintenance.
Q 10- What is CURL?
Ans:
CURL stands for Client URL Library.
CURL is a command line tool for transferring files with URL syntax, supporting FTP, FTPS, HTTP, HTTPS, SCP, SFTP, TFTP, TELNET, DICT, LDAP, LDAPS and FILE. curl supports SSL certificates, HTTP POST, HTTP PUT, FTP uploading, HTTP form based upload, proxies, cookies, user+password authentication (Basic, Digest, NTLM, Negotiate, kerberos…), file transfer resume, proxy tunneling and a busload of other useful tricks.
CURL allows you to connect and communicate to many different types of servers with many different types of protocols. libcurl currently supports the http, https, ftp, gopher, telnet, dict, file, and ldap protocols. libcurl also supports HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading (this can also be done with PHP’s ftp extension), HTTP form based upload, proxies, cookies, and user+password authentication.
Q 11 – What is XML-RPC ?
Ans:
XML-RPC is a remote procedure call protocol which uses XML to encode its calls and HTTP as a transport mechanism. An XML-RPC message is an HTTP-POST request. The body of the request is in XML. A procedure executes on the server and the value it returns is also formatted in XML.
Q 12 – What is the difference between htmlentities() and htmlspecialchars()?
Ans :
i) htmlspecialchars() – Convert some special characters to HTML entities (Only the most widely used). ii) htmlentities() – Convert ALL special characters to HTML entities.
Login as super user ‘root’ in mysql and execute the following commands.
mysql> use mysql;
mysql> create user ‘test’@'%’ identified by ‘test’;
mysql> grant all on *.* to ‘test’@'%’ with grant option;
mysql> flush privileges;
Q 2- What types of privileges are there in MySQL ?
Ans:
There are 4 types of privileges.
i). Global privileges like *.* (all hosts connecting to Mysql db server)
Example: GRANT SELECT, INSERT ON *.* TO ‘someuser’@'somehost’;
ii). Database privileges like .*
Example: GRANT SELECT, INSERT ON mydb.* TO ‘someuser’@'somehost’;
iii). Table privileges like SELECT, INSERT, UPDATE, DELETE
Example: GRANT SELECT, INSERT ON mydb.mytbl TO ‘someuser’@'somehost’;
iv). Column privileges like
Example: GRANT SELECT (col1), INSERT (col1,col2) ON mydb.mytbl TO ‘someuser’@'somehost’;
Q 3- How to find the version of MySQL ?
Ans:
mysql> select version();
Q 4- How do I limit the number of rows I get out of my database?
Ans:
SELECT name FROM table LIMIT [, ] ;
if you want to get the rows between 10 and 20 do the following:
SELECT name FROM table LIMIT 10, 20 ;
Q 5- Is it possible to insert multiple rows using single command in MySQL ?
Ans:
Yes. Please see below example.
INSERT INTO tbl_name (a,b,c) VALUES(1,2,3),(4,5,6),(7,8,9) ;
Q 6- I am getting the following error while logging into “mytest” database.
ERROR 1044 (42000): Access denied for user ‘phpzag’@'localhost’ to database ‘mytest’.
Ans:
Please refer the error to DBA asking for granting the privilege to “mytest” database.
mysql > grant all on test.* to ‘user_name’ @ ‘host_name’ ;
Q 7- What is null value in MySQL ?
Ans:
In MySQL NULL is only equal to NULL, but NULL is not equal to ‘ ‘ ( blank value ) or 0(zero).
Q 8- How can I check if a table in MySQL database already exists?
Ans:
Command : SHOW TABLES LIKE ‘%’;
Q 8- Convert datetime from MST (db servers timezone) into GMT returns NULL value, how to solve it?
Ans:
Database should be updated with timezone value from OS otherwise Mysq
Ans. Magento is a feature-rich eCommerce platform built on open-source technology that provides online merchants with unprecedented flexibility and control over the look, content and functionality of their eCommerce store. Magentos intuitive administration interface features powerful marketing, search engine optimization and catalog-management tools to give merchants the power to create sites that are tailored to their unique business needs. Designed to be completely scalable and backed by Variens support network, Magento offers companies the ultimate eCommerce solution.
Q 2. What is the difference between Mage::getSingletone() andMage::getModel() in Magento
Ans. Mage::getSingletone() always finds for an existing object if not then create that a newobject but Mage::getModel() always creates a new object.
Q 3. Why Magento use EAV database model ?
Ans. In EAV database model, data are stored in different smaller tables rather than storing in asingle table.product name is stored in catalog_product_entity_varchar tableproduct id is stored in catalog_product_entity_int tableproduct price is stored in catalog_product_entity_decimal tableMagento Use EAV database model for easy upgrade and development as this model givesmore flexibility to play with data and attributes.
Q 4. How to upgrade to the latest version using Magento Connect?
Ans. Upgrading Magento to the latest version is a fairly simple task. Copy and Paste this key magento-core/Mage_All_Latest VIA Magento Connect where it states Paste extension key to install:. This will upgrade Magento to the newest version.
Q 5. Explain about the Modules of Magento?
Ans. Magento supports installation of modules through a web-based interface accessible through the administration area of a Magento installation. Modules are hosted on the Magento eCommerce website as a PEAR server. Any community member can upload a module through the website and is made available once confirmed by a member of the Magento team. Modules are installed by entering a module key, available on the module page, into the web based interface.
There are three categories of modules hosted on Magento Connect:
Core Modules
Community Modules
Commercial Modules
Core and Community modules can be installed via the administration area. Commercial module pages provide price information and a link to an external website.
Q 6. What technology used by Magento?
Ans. Magento uses PHP as a web server scripting language and the MySQL Database. The data model is based on the Entity-attribute-value model that stores data objects in tree structures, thus allowing a change to a data structure without changing the database definition.
Q 7. What is MVC structure in Magento?
Ans. The Model-View-Controller (MVC) architecture traces its
origins back to the Smalltalk Programming language and Xerox
Parc. Since then, there have been many systems that describe
their architecture as MVC. Each system is slightly
different, but all have the goal of separating data access,
business logic, and user-interface code from one another.
Q 8. What is benefit of namespace (package) in magento?
Ans. We can have more than one module with same name but they should be placed in different namespaces. All magento core modules are contained in mage namespace.
core/Mage/Catalog
and all custom modules are placed in
local/CustomModule
Q 9. How to include CMS block in template file(.phtml)?
Ans. Access block’s content from .phtml template file by :
Q 10. How to add an external javascript/css file to Magento?
Ans.
css/yourstyle.css
or
skin_jsjs/ yourfile.js
skin_csscss/yourstyle. css
Q 11. What are handles in magento (layout)?
Ans. Handles are basically used for controlling the structure of the page like which block will be displayed and where. First level child elements of the node are called layout handles. Every page request can have several unique Handles. The handle is called for every page. handle for products belongs to virtual product type, PRODUCT_TYPE_simple is called for product details page of simple product type and PRODUCT_TYPE_virtual is called for the virtual product detail page and customer_logged_in handle is called only if customer is logged in. The muster_index_index handle is created by combining the frontName (muster), Action Controller (index), and Action Controller Action Method (index) into a single string and this handle will be called only when /zag/index/index url is accessed.
Q 12. What is in magento?
Ans. The routers tag allow us to decide frontname for each module. The tag is defined in config.xml file of module. For Namespace_MyModule frontname is moduleurl so the url will be like :
websiteurl.com/moduleurl/controllername/actionname
standard
Namespace_MyModule
moduleurl
Q 13. Which factors affect performance of magento?
Ans.
1. EAV structure of magento database, even for retrieving single entity the query becomes very complex .
2. Magento’s template system involves a lot of recursive rendering
3. Huge XML trees built up for layout configuration, application configuration settings
Q 14. How to improve magento performance?
Ans.
Enabled magento caching
MySQL Query caching
Enable Gzip Compression
Disable any unused modules
Disable the Magento log
Optimise your images
Combine external CSS/JS into one file
Enable Apache KeepAlives: Make sure your Apache configuration has KeepAlives enabled.
Q 15. How to get the Total Price of items currently in the Cart?
Ans. Steps to create custom magento module:
Namespace : Zag
Module Name : Mymodule
1. Create directory Mymodule in app/code/local/Zag
2. Create Block, controllers, etc, Module directories. Create controller, block and module file as required.
3. Create module configuration file (app/code/local/Zag/Mymodule/etc/config.xml).
4. Create xml file (app/etc/modules/Zag_ Mymodule.xml)to enable/disable module and tell magento system from which code pool that module will be taken.
Q 18. How to set different themes for each store?
Ans. Go to : System>Designs
Then, add new design change or edit existing. You can select Store and Custom Design.
Q 19. How to make product’s custom attribute searchable in adavance search?
Ans. Go to : Catalog > Attribues > Manage Attribues
Edit the attribute and select “Yes” for Use in Advanced Search.
Q 20. How to fetch 5 bestsellers products programmatically?
Ans.
Mage::getResourceModel(‘reports/product_collection’)
->addOrderedQty()
->addAttributeToSelect(‘*’)
->setPage(1, 5)
->load();
Q 1- What is the difference between HTML and HTML5 ?
Ans: HTML5 is nothing more then upgraded version of HTML where in HTML5 Lot of new future like Video, Audio/mp3, date select function , placeholder , Canvas, 2D/3D Graphics, Local SQL Database added so that no need to do external plugin like Flash player or other library
Q 2- What is the <!DOCTYPE> ? Is it necessary to use in HTML5 ?
Ans: The <!DOCTYPE> is an instruction to the web browser about what version of HTML the page is written in. AND The <!DOCTYPE> tag does not have an end tag and It is not case sensitive.
The <!DOCTYPE> declaration must be the very first thing in HTML5 document, before the <html> tag. As In HTML 4.01, all <! DOCTYPE > declarations require a reference to a Document Type Definition (DTD), because HTML 4.01 was based on Standard Generalized Markup Language (SGML). WHERE AS HTML5 is not based on SGML, and therefore does not require a reference to a Document Type Definition (DTD).
Q 3- How many New Markup Elements you know in HTML5
Ans: Below are the New Markup Elements added in HTML5
Tag
Description
<article>
Specifies independent, self-contained content, could be a news-article, blog post, forum post,
or other articles which can be distributed independently from the rest of the site.
<aside>
For content aside from the content it is placed in. The aside content should
be related to the surrounding content
<bdi>
For text that should not be bound to the text-direction of its parent elements
<command>
A button, or a radiobutton, or a checkbox
<details>
For describing details about a document, or parts of a document
<summary>
A caption, or summary, inside the details element
<figure>
For grouping a section of
stand-alone content, could be a video
<figcaption>
The caption of the figure section
<footer>
For a footer of a document or section, could include the name of the author, the
date of the document, contact information, or copyright information
<header>
For an introduction of a document or section, could include navigation
<hgroup>
For a section of headings, using <h1> to <h6>, where the largest is the main
heading of the section, and the others are sub-headings
<mark>
For text that should be highlighted
<meter>
For a measurement, used only if the maximum and minimum values are known
<nav>
For a section of navigation
<progress>
The state of a work in progress
<ruby>
For ruby annotation (Chinese notes or characters)
<rt>
For explanation of the ruby annotation
<rp>
What to show browsers that do not support the ruby element
<section>
For a section in a document. Such as chapters, headers, footers, or any
other sections of the document
<time>
For defining a time or a date, or both
<wbr>
Word break. For defining a line-break opportunity.
Q 4- What are the New Media Elements in HTML5? is canvas element used in HTML5
Ans: Below are the New Media Elements have added in HTML5
Tag
Description
<audio>
For multimedia content, sounds, music or other audio streams
<video>
For video content, such as a movie clip or other video streams
<source>
For media resources for media elements, defined inside video or audio
elements
<embed>
For embedded content, such as a plug-in
<track>
For text tracks used in mediaplayers
yes we can use Canvas element in html5 like <canvas></canvas>
Q 5- Do you know New Input Type Attribute in HTML5
Ans: Yes we can use below new input type Attribute in HTML5
Type
Value
tel
The input is of type telephone number
search
The input field is a search field
url
a URL
email
One or more email addresses
datetime
A date and/or time
date
A date
month
A month
week
A week
time
The input value is of type time
datetime-local
A local date/time
number
A number
range
A number in a given range
color
A hexadecimal color, like #82345c
placeholder
Specifies a short hint that describes the expected value of an input field
Q 6- How to add video and audio in HTML5
Ans: The canvas element is used to draw graphics images on a web page by using javascript like below
Ans: Before HTML5 LocalStores was done with cookies. Cookies are not very good for large amounts of data, because they are passed on by every request to the server, so it was very slow and in-effective.
In HTML5, the data is NOT passed on by every server request, but used ONLY when asked for. It is possible to store large amounts of data without affecting the website’s performance.and The data is stored in different areas for different websites, and a website can only access data stored by itself.
And for creating localstores just need to call localStorage object like below we are storing name and address
Q 8- What is the sessionStorage Object in html5 ? How to create and access?
Ans: The sessionStorage object stores the data for one session. The data is deleted when the user closes the browser window. like below we can create and access a sessionStorage here we created “name” as session
var pcdsCanvas=document.getElementById(“phpzagCanvas”);
var pcdsText=pcdsCanvas.getContext(“2d”);
pcdsText.fillStyle=“#82345c”;
pcdsText.fillRect(0,0,150,75);
</script>
Q 10- What purpose does HTML5 serve?
Ans: HTML5 is the proposed next standard for HTML 4.01, XHTML 1.0 and DOM Level 2 HTML. It aims to reduce the need for proprietary plug-in-based rich internet application (RIA) technologies such as Adobe Flash, Microsoft Silverlight, Apache Pivot, and Sun JavaFX.
Q 11- What is the difference between HTMl5 Application cache and regular HTML browser cache?
Ans: HTML5 specification allows browsers to prefetch some or all of a website assets such as HTML files, images, CSS, JavaScript, and so on, while the client is connected. It is not necessary for the user to have accessed this content previously, for fetching this content. In other words, application cache can prefetch pages that have not been visited at all and are thereby unavailable in the regular browser cache. Prefetching files can speed up the site’s performance, though you are of course using bandwidth to download those files initially.
Q 12- HOW DO YOU PLAY A AUDIO USING HTML5?
Ans:
We can display audio using the tag as shown below:
Q 15- WHAT ARE THE NEW APIS PROVIDED BY THE HTML 5 STANDARD? GIVE A BRIEF DESCRIPTION OF EACH?
Ans:
The canvas element: Canvas consists of a drawable region defined in HTML code with height and width attributes. JavaScript code may access the area through a full set of drawing functions similar to other common 2D APIs, thus allowing for dynamically generated graphics. Some anticipated uses of the canvas include building graphs, animations, games, and image composition.
Timed media playback
Offline storage database
Document editing
Drag-and-drop
Cross-document messaging
Browser history management
MIME type and protocol handler registration
Q 16- WHAT OTHER ADVANTAGES DOES HTML5 HAVE?
Ans: a) Cleaner markup b) Additional semantics of new elements like <header>, <nav>, and <time> c) New form input types and attributes that will (and in Opera’s case, do) take the hassle out of scripting forms.
Q 17- GIVE AN EXAMPLE OF NEW ELEMENTS IN HTML5 TO SUPPORT MULTIMEDIA AND GRAPHICS?
Ans: HTML5 introduced many elements such as , instead of
Q 19- WHAT IS THE DIFFERENCE BETWEEN HTML5 APPLICATION CACHE AND REGULATE HTML BROWSER CACHE?
Ans:
The new HTML5 specification allows browsers to prefetch some or all of a website assets such as HTML files, images, CSS, JavaScript, and so on, while the client is connected. It is not necessary for the user to have accessed this content previously, for fetching this content. In other words, application cache can prefetch pages that have not been visited at all and are thereby unavailable in the regular browser cache. Prefetching files can speed up the site’s performance, though you are of course using bandwidth to download those files initially.
Q 20- WHAT PURPOSE DOES HTML5 SERVE?
Ans:
HTML5 is the proposed next standard for HTML 4.01, XHTML 1.0 and DOM Level 2 HTML. It aims to reduce the need for proprietary plug-in-based rich internet application (RIA) technologies such as Adobe Flash, Microsoft Silver light, Apache Pivot, and Sun JavaFX.
Q 21 – WHAT IS THE STATUS OF THE DEVELOPMENT OF THE HTML 5 STANDARD?
Ans: HTML5 is being developed as the next major revision of HTML (HyperText Markup Language), the core markup language of the World Wide Web. The Web Hypertext Application Technology Working Group (WHATWG) started work on the specification in June 2004 under the name Web Applications 1.0.[1] As of March 2010[update], the specification is in the Draft Standard state at the WHATWG, and in Working Draft state at the W3C.
1- What’s 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- What Is a Session?
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 the difference between $message and $$message?
Anwser 1:
$message is a simple variable whereas $$message is a reference variable. Example:
$user = ‘bob’
is equivalent to
$holder = ‘user’;
$$holder = ‘bob’;
Anwser 2:
They are both variables. But $message is a variable with a fixed name. $$message is a variable who’s name is stored in $message. For example, if $message contains “var”, $$message is the same as $var. 4- What Is a Persistent Cookie?
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. 5- How do you define a constant?
Via define() directive, like define (“MYCONSTANT”, 100); 6- What are the differences between require and include, include_once?
Anwser 1:
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.
Anwser 2:
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.
Anwser 3:
All three are used to an include file into the current page.
If the file is not present, require(), calls a fatal error, while in include() does not.
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. It des not call a fatal error if file not exists. require_once() does the same as include_once(), but it calls a fatal error if file not exists.
Anwser 4:
File will not be included more than once. If we want to include a file once only and further calling of the file will be ignored then we have to use the PHP function include_once(). This will prevent problems with function redefinitions, variable value reassignments, etc. 7- What is meant by urlencode and urldecode?
Anwser 1:
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.
Anwser 2:
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.
You will get “http://domain.com/submit.php?disc=10%2E00%25″. 8- What is 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 9- How can I 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. 10- Would 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. 11- What is the functionality of the functions STRSTR() and STRISTR()?
string strstr ( string haystack, string needle ) returns part of haystack string from the first occurrence of needle to the end of haystack. This function is case-sensitive.
stristr() is idential to strstr() except that it is case insensitive. 12- When are you supposed to use endif to end the conditional statement?
When the original if was followed by : and then the code block without braces. How can we 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;
} 13- What is 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. 14- What is 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. 15- How do I find out the number of parameters passed into function9. ?
func_num_args() function returns the number of parameters passed in. 16- If the 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. 17- How To 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 TECHPreparation.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?’.$comment.’”>’
.”It’s an average site.</a></p>”);
print(“</html>”);
?> 18- How do you call a constructor for a parent class?
parent::constructor($value) 19- WHAT ARE THE DIFFERENT TYPES OF ERRORS IN PHP?
Here are three basic types of runtime errors in PHP:
1. Notices: These are trivial, 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 you can change this default behavior.
2. Warnings: These are more serious errors – for example, 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.
Internally, these variations are represented by twelve different error types 20- What’s the special meaning of __sleep and __wakeup?
__sleep returns the array of all the variables than need to be saved, while __wakeup retrieves them. 21- How can we submit a form without a submit button?
If you don’t want to use the Submit button to submit a form, you can use normal hyper links to submit a form. But you need to use some JavaScript code in the URL of the link. For example:
1- Why doesn’t the following code print the newline properly? <?php $str = ‘Hello, there.\nHow are you?\nThanks for visiting techpreparation’; print $str; ?>
Because inside the single quotes the \n character is not interpreted as newline, just as a sequence of two characters – \ and n. 2- Would you initialize your strings with single quotes or double quotes?
Since the data inside the single-quoted string is not parsed for variable substitution, it’s always a better idea speed-wise to initialize a string with single quotes, unless you specifically need variable substitution. 3- How can we extract string ‘abc.com ‘ from a string http://info@abc.com using regular expression of php?
We can use the preg_match() function with “/.*@(.*)$/” as
the regular expression pattern. For example:
preg_match(“/.*@(.*)$/”,”http://info@abc.com”,$data);
echo $data[1]; 4- What are the differences between GET and POST methods in form submitting, give the case where we can use GET and we can use POST methods?
Anwser 1:
When we submit a form, which has the GET method it displays pair of name/value used in the form at the address bar of the browser preceded by url. Post method doesn’t display these values.
Anwser 2:
When you want to send short or small data, not containing ASCII characters, then you can use GET” Method. But for long data sending, say more then 100 character you can use POST method.
Once most important difference is when you are sending the form with GET method. You can see the output which you are sending in the address bar. Whereas if you send the form with POST” method then user can not see that information.
Anwser 3:
What are “GET” and “POST”?
GET and POST are methods used to send data to the server: With the GET method, the browser appends the data onto the URL. With the Post method, the data is sent as “standard input.”
Major Difference
In simple words, in POST method data is sent by standard input (nothing shown in URL when posting while in GET method data is sent through query string.
Ex: Assume we are logging in with username and password.
GET: we are submitting a form to login.php, when we do submit or similar action, values are sent through visible query string (notice ./login.php?username=…&password=… as URL when executing the script login.php) and is retrieved by login.php by $_GET['username'] and $_GET['password'].
POST: we are submitting a form to login.php, when we do submit or similar action, values are sent through invisible standard input (notice ./login.php) and is retrieved by login.php by $_POST['username'] and $_POST['password'].
POST is assumed more secure and we can send lot more data than that of GET method is limited (they say Internet Explorer can take care of maximum 2083 character as a query string).
Anwser 4:
In the get method the data made available to the action page ( where data is received ) by the URL so data can be seen in the address bar. Not advisable if you are sending login info like password etc. In the post method the data will be available as data blocks and not as query string in case of get method.
Anwser 5:
When we submit a form, which has the GET method it pass value in the form of query string (set of name/value pair) and display along with URL. With GET we can a small data submit from the form (a set of 255 character) whereas Post method doesn’t display value with URL. It passes value in the form of Object and we can submit large data from the form.
Anwser 6:
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 $_POST array stores data submitted by the POST method.
On the browser side, the difference is that data submitted by the GET method will be displayed in the browser’s address field. Data submitted by the POST method will not be displayed anywhere on the browser.
GET method is mostly used for submitting a small amount and less sensitive data. POST method is mostly used for submitting a large amount or sensitive data. 5- What is the difference between the functions unlink and unset?
unlink() is a function for file system handling. It will simply delete the file in context.
unset() is a function for variable management. It will make a variable undefined. 6- How come the code works, but doesn’t for two-dimensional array of mine?
Any time you have an array with more than one dimension, complex parsing syntax is required. print “Contents: {$arr[1][2]}” would’ve worked. 7- How can we register the variables into a session?
session_register($session_var);
$_SESSION['var'] = ‘value’; 8- What is the difference between characters \023 and \x23?
The first one is octal 23, the second is hex 23. 9- With a heredoc syntax, do I get variable substitution inside the heredoc contents?
Yes. 10- How can we submit form without a submit button?
We can use a simple JavaScript code linked to an event trigger of any form field. In the JavaScript code, we can call the document.form.submit() function to submit the form. For example: <input type=button value=”Save” onClick=”document.form.submit()”> 11- How can we create a database using PHP and mysql?
We can create MySQL database with the use of mysql_create_db($databaseName) to create a database. 12- How many ways we can retrieve the date in result set of mysql using php?
As individual objects so single record or as a set or arrays. 13- Can we use include (“abc.php”) two times in a php page “makeit.php”?
Yes. For printing out strings, there are echo, print and printf. Explain the differences.
echo is the most primitive of them, and just outputs the contents following the construct to the screen. print is also a construct (so parentheses are optional when calling it), but it returns TRUE on successful output and FALSE if it was unable to print out the string. However, you can pass multiple parameters to echo, like:
and it will output the string “Welcome to techpreparations!” print does not take multiple parameters. It is also generally argued that echo is faster, but usually the speed advantage is negligible, and might not be there for future versions of PHP. printf is a function, not a construct, and allows such advantages as formatted output, but it’s the slowest way to print out data out of echo, print and printf. 14- I am writing an application in PHP that outputs a printable version of driving directions. It contains some long sentences, and I am a neat freak, and would like to make sure that no line exceeds 50 characters. How do I accomplish that with PHP?
On large strings that need to be formatted according to some length specifications, use wordwrap() or chunk_split(). 15- What’s the output of the ucwords function in this example?
$formatted = ucwords(“TECHPREPARATIONS IS COLLECTION OF INTERVIEW QUESTIONS”);
print $formatted;
What will be printed is TECHPREPARATIONS IS COLLECTION OF INTERVIEW QUESTIONS.
ucwords() makes every first letter of every word capital, but it does not lower-case anything else. To avoid this, and get a properly formatted string, it’s worth using strtolower() first. 16- What’s the difference between htmlentities() and htmlspecialchars()?
htmlspecialchars only takes care of <, >, single quote ‘, double quote ” and ampersand. htmlentities translates all occurrences of character sequences that have different meaning in HTML. 17- How can we extract string “abc.com” from a string “mailto:info@abc.com?subject=Feedback” using regular expression of PHP?
$text = “mailto:info@abc.com?subject=Feedback”;
preg_match(‘|.*@([^?]*)|’, $text, $output);
echo $output[1];
Note that the second index of $output, $output[1], gives the match, not the first one, $output[0]. 18- So if md5() generates the most secure hash, why would you ever use the less secure crc32() and sha1()?
Crypto usage in PHP is simple, but that doesn’t mean it’s free. First off, depending on the data that you’re encrypting, you might have reasons to store a 32-bit value in the database instead of the 160-bit value to save on space. Second, the more secure the crypto is, the longer is the computation time to deliver the hash value. A high volume site might be significantly slowed down, if frequent md5() generation is required. 19- How can we destroy the session, how can we unset the variable of a session?
session_unregister() – Unregister a global variable from the current session
session_unset() – Free all session variables 20- What are the different functions in sorting an array?
Sorting functions in PHP:
asort()
arsort()
ksort()
krsort()
uksort()
sort()
natsort()
rsort() 21- How can we know the count/number of elements of an array?
2 ways:
a) sizeof($array) – This function is an alias of count()
b) count($urarray) – This function returns the number of elements in an array.
Interestingly if you just pass a simple var instead of an array, count() will return 1. 22- How many ways we can pass the variable through the navigation between the pages?
At least 3 ways:
1. Put the variable into session in the first page, and get it back from session in the next page.
2. Put the variable into cookie in the first page, and get it back from the cookie in the next page.
3. Put the variable into a hidden form field, and get it back from the form in the next page.
1- What is the difference between CHAR and VARCHAR data types?
CHAR is a fixed length data type. CHAR(n) will take n characters of storage even if you enter less than n characters to that column. For example, “Hello!” will be stored as “Hello! ” in CHAR(10) column.
VARCHAR is a variable length data type. VARCHAR(n) will take only the required storage for the actual number of characters entered to that column. For example, “Hello!” will be stored as “Hello!” in VARCHAR(10) column. 2- How can we encrypt and decrypt a data present in a mysql table using mysql?
AES_ENCRYPT() and AES_DECRYPT() Will comparison of string “10″ and integer 11 work in PHP?
Yes, internally PHP will cast everything to the integer type, so numbers 10 and 11 will be compared. 3- What is the functionality of MD5 function in PHP?
string md5(string)
It calculates the MD5 hash of a string. The hash is a 32-character hexadecimal number. 4- How can I load data from a text file into a table?
The MySQL provides a LOAD DATA INFILE command. You can load data from a file. Great tool but you need to make sure that:
a) Data must be delimited
b) Data fields must match table columns correctly 5- What is meant by MIME?
Answer 1:
MIME is Multipurpose Internet Mail Extensions is an Internet standard for the format of e-mail. However browsers also uses MIME standard to transmit files. MIME has a header which is added to a beginning of the data. When browser sees such header it shows the data as it would be a file (for example image)
Some examples of MIME types:
audio/x-ms-wmp
image/png
application/x-shockwave-flash
Answer 2:
Multipurpose Internet Mail Extensions.
WWW’s ability to recognize and handle files of different types is largely dependent on the use of the MIME (Multipurpose Internet Mail Extensions) standard. The standard provides for a system of registration of file types with information about the applications needed to process them. This information is incorporated into Web server and browser software, and enables the automatic recognition and display of registered file types. … 6- How can we know that a session is started or not?
A session starts by session_start() function.
This session_start() is always declared in header portion. it always declares first. then we write session_register(). 7- What are the differences between mysql_fetch_array(), mysql_fetch_object(), mysql_fetch_row()?
Answer 1:
mysql_fetch_array() -> Fetch a result row as a combination of associative array and regular array.
mysql_fetch_object() -> Fetch a result row as an object.
mysql_fetch_row() -> Fetch a result set as a regular array().
Answer 2:
The difference between mysql_fetch_row() and mysql_fetch_array() is that the first returns the results in a numeric array ($row[0], $row[1], etc.), while the latter returns a the results an array containing both numeric and associative keys ($row['name'], $row['email'], etc.). mysql_fetch_object() returns an object ($row->name, $row->email, etc.). 8- If we login more than one browser windows at the same time with same user and after that we close one window, then is the session is exist to other windows or not? And if yes then why? If no then why?
Session depends on browser. If browser is closed then session is lost. The session data will be deleted after session time out. If connection is lost and you recreate connection, then session will continue in the browser. 9- What is the difference between PHP4 and PHP5?
PHP4 cannot support oops concepts and Zend engine 1 is used.
PHP5 supports oops concepts and Zend engine 2 is used.
Error supporting is increased in PHP5.
XML and SQLLite will is increased in PHP5. 10- Can we use include(abc.PHP) two times in a PHP page makeit.PHP”?
Yes we can include that many times we want, but here are some things to make sure of:
(including abc.PHP, the file names are case-sensitive)
there shouldn’t be any duplicate function names, means there should not be functions or classes or variables with the same name in abc.PHP and makeit.php 11- What is meant by nl2br()?
Anwser1:
nl2br() inserts a HTML tag <br> before all new line characters \n in a string.
echo nl2br(“god bless \n you”);
output:
god bless<br>
you 12- In how many ways we can retrieve data in the result set of MYSQL using PHP?
mysql_fetch_array – Fetch a result row as an associative array, a numeric array, or both
mysql_fetch_assoc – Fetch a result row as an associative array
mysql_fetch_object – Fetch a result row as an object
mysql_fetch_row —- Get a result row as an enumerated array 13- What are the functions for IMAP?
imap_body – Read the message body
imap_check – Check current mailbox
imap_delete – Mark a message for deletion from current mailbox
imap_mail – Send an email message 14- What are encryption functions in PHP?
CRYPT()
MD5() 15- What is the difference between htmlentities() and htmlspecialchars()?
htmlspecialchars() – Convert some special characters to HTML entities (Only the most widely used)
htmlentities() – Convert ALL special characters to HTML entities 16- What is the functionality of the function htmlentities?
htmlentities() – Convert all applicable characters to HTML entities
This function is identical to htmlspecialchars() in all ways, except with htmlentities(), all characters which have HTML character entity equivalents are translated into these entities. 17- How can we get the properties (size, type, width, height) of an image using php image functions?
To know the image size use getimagesize() function
To know the image width use imagesx() function
To know the image height use imagesy() function 18- How can we increase the execution time of a php script?
By the use of void set_time_limit(int seconds)
Set the number of seconds a script is allowed to run. If this is reached, the script returns a fatal error. The default limit is 30 seconds or, if it exists, the max_execution_time value defined in the php.ini. If seconds is set to zero, no time limit is imposed.
When called, set_time_limit() restarts the timeout counter from zero. In other words, if the timeout is the default 30 seconds, and 25 seconds into script execution a call such as set_time_limit(20) is made, the script will run for a total of 45 seconds before timing out. 19- How to set cookies?
setcookie(‘variable’,'value’,'time’)
;
variable – name of the cookie variable
value – value of the cookie variable
time – expiry time
Example: setcookie(‘Test’,$i,time()+3600);
Test – cookie variable name
$i – value of the variable ‘Test’
time()+3600 – denotes that the cookie will expire after an one hour
1- What is 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. 2- How do I find out the number of parameters passed into function9. ?
func_num_args() function returns the number of parameters passed in. 3- If the 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. 4- How To 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 TECHPreparation.com:</p>”);
$comment = ‘I want to say: “It\’s a good site! :->”‘;
$comment = ‘This visitor said: “It\’s an average site! “‘;
$comment = urlencode($comment);
print(“<p>”
.’<a href=”processing_forms.php?’.$comment.’”>’
.”It’s an average site.</a></p>”);
print(“</html>”);
?> 5- Are objects passed by value or by reference?
Everything is passed by value. 6- What are the differences between DROP a table and TRUNCATE a table?
DROP TABLE table_name – This will delete the table and its data.
TRUNCATE TABLE table_name – This will delete the data of the table, but not the table definition. 7- How do you call a constructor for a parent class?
parent::constructor($value) 8- WHAT ARE THE DIFFERENT TYPES OF ERRORS IN PHP?
Here are three basic types of runtime errors in PHP:
1. Notices: These are trivial, 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 you can change this default behavior.
2. Warnings: These are more serious errors – for example, 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.
Internally, these variations are represented by twelve different error types 9- What’s the special meaning of __sleep and __wakeup?
__sleep returns the array of all the variables than need to be saved, while __wakeup retrieves them. 10- How can we submit a form without a submit button?
If you don’t want to use the Submit button to submit a form, you can use normal hyper links to submit a form. But you need to use some JavaScript code in the URL of the link. For example:
Q- What is htaccess? Why do we use this and Where?
Answers :.htaccess files are configuration files of Apache Server which provide
a way to make configuration changes on a per-directory basis. A file,
containing one or more configuration directives, is placed in a particular
document directory, and the directives apply to that directory, and all
subdirectories thereof.
“‘;
