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webdevelopmentcompanyindia · 4 years ago

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Five Common PHP Problems and Solutions

PHP is a vast subject that needs lots of study to get done. It is a most-used open fount general-purpose scripting language that is particularly satisfied for web development and can be inserted into HTML. Today we are giving answers of top Php related question which will help you to done the process. Here solutions are provided by the top PHP Development Company, AResourcePool.

How to store image in core Php using input type file?

Are you looking for the ways to upload or store an image in core Php using input type file? If yes, so here we are.

Php script is very popular as it is using with a HTML form to let the users to upload files to the different server. At first the files are uploaded into a transitory directory as well as, it moved to a target by a PHP script.

Here are some procedures of uploading a file. So, here you go:

· Open a page which contains a HTML where you can feature an image, text files, and browser button as well as submit button.

· Now, click on the browser button and select the desired file to upload from your computer or laptop.

· You will now see the entire file of the selected path. So, choose where you wanna store it and press submit button.

· The file will send to the directory which is only temporary on the server.

· Php script was particular as the outline handler in the form’s action attribute. Now check is the file exist and then copy to the directory.

· You can make sure your success by using PHP script.

Meanwhile, it is really important to seek permission when writing files for permanent location or for temporary location. Whatever file you are uploading can be the image file or it can be the text file or whatever document you are uploading.

How to create an upload form?

To create an upload form you will need HTM coding because it has certain attribute of post as well as enctype attribute which is set to multipart.

<?php

if(isset($_FILES[‘image’])){

$errors= array();

$file_name = $_FILES['image’]['name’];

$file_size =$_FILES['image’]['size’];

$file_tmp =$_FILES['image’]['tmp_name’];

$file_type=$_FILES['image’]['type’];

$file_ext=strtolower(end(explode(’.’,$_FILES['image’]['name’])));

$extensions= array(“jpeg”,“jpg”,“png”);

if(in_array($file_ext,$extensions)=== false){

$errors[]=“extension not allowed, please choose a JPEG or PNG file.”;

}

if($file_size > 2097152){

$errors[]='File size must be excately 2 MB’;

}

if(empty($errors)==true){

move_uploaded_file($file_tmp,“images/”.$file_name);

echo “Success”;

}else{

print_r($errors);

}

<html>

<body>

</form>

</body>

</html>

How can I test to see if value is 0 or null in PHP?

Php is a vast subject that contains many elements and one of the major elements of Php is to check 0, null or empty and isset status. It has various functions to check whether it is good or not or to test the value of the variables. There are three important functions of Php such as isset(), empty() and is_null(). This factors help to return a Boolean value. Boolean value is the used to determine the value of these functions. The result would be unexpected if it is not used in a right ways. There are two functions which functions opposite isset() and empty(). Well, it is not always true there is certain difference between all. So, here have a look at these functions:

1. isset()From PHP manual – isset():

Isset is used to decide that if a variable is set and is not NULL. If we say in other words then, it is used to determine the return is true only when not null is the variable.

2. empty()From PHP Manual – empty():

Empty is used to decide that if a variable is empty.If we talk in other terms then, it will return true if the variable is empty. It will show false, array(), NULL, “0?, 0, and an unset variable.

3. is_null()From PHP Manual – is_null():

Null is used to find if a variable is Null or not. In other words if we say then the returns true then, only when the variable shows null result. is_null() is opposite of isset(), except for one difference that isset() can be applied to unknown variables, but is_null() only to declared variables.

How to delete row from table using PHP pdo?

You can utilize the assignments table in the example database for the showing. Before going ahead with this instructional exercise, you ought to pursue the PHP MySQL make table instructional exercise to make the errands table and addition test information for rehearsing.

PHP MySQL Delete: Tasks Table:To erase information in a table, you utilize the accompanying advances: Associate with the MySQL database by making another case of the PDO object.

First of all, build a DELETE explanation to erase a column, numerous lines, or all lines in a table. On the off chance that you need to erase all columns in a major table rapidly and all the more proficiently, you utilize the TRUNCATE TABLE proclamation. Execute the DELETE articulation by calling the executive() strategy for the PDO object or the execute() technique for the PDOStatement object.

· PHP MySQL Delete information models

· PHP MySQL: erase a solitary column model

· To erase a solitary column in a table, you utilize the DELETE articulation with a WHERE condition that determines which line to erase.

· The accompanying content erases a column with id 2 in the assignments table.

How it functions?

When we talk about__construct() technique for the DeleteDataDemo class, we interface with the MySQL database by starting a case of the PDO class, and in the __destruct() strategy, we close the database association. The erase() technique acknowledges the id as the contention. In the first place, we call the get ready() technique for the PDO item to set up the DELETE explanation for execution, and after that we pass an exhibit that contains values comparing to the named placeholders in the DELETE proclamation to the execute() strategy for the PDOStatement object.

To erase the undertaking with id 2, we make an example of the DeleteDataDemo class and call the erase() strategy.

PHP MySQL: erase all columns in a table precedents

There are two different ways to erase all columns in a table:

· Issue a DELETE explanation without a WHERE statement.

· Issue a TRUNCATE TABLE explanation.

Getting Data from Multiple Databases:

There can be different issues which can face while fetching data from multiple databases but, issue you will have is consolidating the information. In a solitary database you keep up information honesty by characterizing outside keys. Different tables may have things identified with clients, so they may have a user_id field.

In a solitary database you would characterize a remote key connection between that user_id field and the id field on the client table, which means just existing id esteems from the client table, could be embedded in the othertable::user_id field. You can’t do outside key connections between tables in various databases, so I don’t have the foggiest idea how you’re going to interface the two arrangements of information into a solitary dataset.

Notwithstanding, expect you have a pseudo remote key, as above, however itwon’t be utilized by the databases to look after honesty. At that point need to do some sort of for/for each circle more than one dataset, remove the key which joins it to the next dataset, at that point glance through the second dataset for the coordinating key.

So, there are certain steps which involved in it so, have a look:

· make first association config ($conn1 = mysqli_connect($server1, $username, $password, $dbname)

· make second association config ($conn2 = mysqli_connect($server2, $username, $password, $dbname2);)

· select information with $conn config and store into $result variable (exhibit)

· for each $result, embed it into second database utilizing $conn2

How to display data record in database from vertical to horizontal:

There are many different ways to arrange data in a vertical to the horizontal database in Php. You will get two favourable circumstances and weaknesses to these strategies for social database information association. I completely depend on the requirements of the business as well it also depends on the need for the development.

The traditional way of any data in a table is a horizontal layout. Whatever data is recorded is go in a row and columns format runs horizontally. On the other hand, the second way is vertical. This way is very specific as well as it stores data that only have a column for real data. Here have a look at the example of data record in database from vertical to horizontal.

Table for Horizontal:

First_Name

Last_Name

Dept

Sex

123

Vlad

Kofman

234

Jim

Cramer

Marketing

456

Olimpia

Dukakis

Accounting

Table for Vertical

Key

Value

123

First_Name

Vlad

234

First_Name

Jim

456

First_Name

Olimpia

123

Last_Name

Kofman

234

Last_Name

Cramer

456

Last_Name

Dukakis

123

Dept

234

Dept

Marketing

456

Dept

Accounting

123

Sex

234

Sex

456

Sex

How enable in php long query strings:

Selecting Encrypted Username from DB:

There is very common question always hit the mind of the users that how Selecting Encrypted Username from DB? So, to encrypt the process does the data in the database unreadable from data in word processors. There can be no one decipher of its data when the database is encrypted.

Any database can be encrypted by utilizing the standard access menus. In both, the cases database that you are encrypting cannot be opened.

Follow this step to Encrypted Username from DB:

· Step 1: Select the tool by going to the setting. You will get options like Encrypt/Decrypt Database in the menu options.

· Step 2: You will see the encrypt/decrypt database dialogue from which choose the file which you want to encrypt. Press Okay.

· Step 3: If a user chooses the name which already exists in the files then, access will remove the original file after it concludes the process of encryption is successful. One of the best things that you can do in this situation is to take back up of the original database.

Encrypting with Code:

If you have used runtime version of Access to distribute your application and wants to give all the Php users the capability to encrypt the database you have to enter database course such as ADO. The following code will look like this:

Sub Encrypt(strDBNotEncrypted As String, _

strDBEncrypted As String)

Dim je As Nwe JRO.JetEngine

Je.CompactDatabase SourceConnection:=“Data Source=” _

& strDBNotEncrypted & “;”, _

DestConnection:=“Data Source=” & strDBEncrypted & _

"; Jet OLEDB:Encrypt Database=True"

End Sub

That’s all the folk about Php. If you are looking for such services you can contact Aresourcepool. The company has the best solution for all the above mentioned concept.

#php development company #php development #php development company india

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t-baba · 5 years ago

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PHP Magic Methods Cheatsheet

In this post, I'll give you a cheetsheet quick reference to all the magic methods available in PHP.

Whether you are a seasoned PHP developer or a novice in PHP development, if you’ve worked with OOP in PHP, then you’re using at least a couple of PHP magic methods already. However, if you have not heard of PHP magic methods yet, let me introduce them:

The function names __construct(), __destruct(), __call(), __callStatic(), __get(), __set(), __isset(), __unset(), __sleep(), __wakeup(), __toString(), __invoke(), __set_state(), __clone() and __debugInfo() are magical in PHP classes. You cannot have functions with these names in any of your classes unless you want the magic functionality associated with them. All magic methods MUST be declared as public.

If you’re wondering why these methods are called magic methods, it’s because of the fact that if you define one of these methods in your class, it’ll be called automatically and you are just supposed to define what should happen within it. The best example of the magic method is the __construct() function which is called automatically when the object is instantiated.

In general, magic methods in PHP allow you to perform various kinds of operations with objects. It also allows you to handle certain kinds of situations by manipulating objects.

PHP Magic Methods

The aim of this article is to go through all the magic methods in PHP and explain them each briefly.

The __contruct() Method

If you define this method in your class, it’ll be called automatically when an object is instantiated. The purpose of this method is to assign some default values to object properties. This method is also called a constructor.

Let’s have a look at a quick example to understand how it works:

<?php class Student { private $name; private $email; public function __construct($name, $email) { $this->name = $name; $this->email = $email; } } $objStudent = new Student('John', '[email protected]'); ?>

In the above example, when you instantiate a new object by with new student('John','[email protected]'), it calls the __construct() method in the first place. In the __construct() method, we’ve assigned values passed in the arguments to the object properties.

The __destruct() Method

The __destruct() method is called a destructor and it’s called when the object is destroyed. Generally, it’s also called when the script is stopped or exited. The purpose of this method is to provide an opportunity to save the object state or any other cleanups you would want to perform.

Let’s have a look at the following example:

<?php class Student { private $name; private $email; public function __construct($name, $email) { $this->name = $name; $this->email = $email; } public function __destruct() { echo 'This will be called when the script is shut down...'; // save object state/other clean ups } } $objStudent = new Student('John', '[email protected]'); ?>

The __set() Method

The __set() magic method is called when you try to set data to inaccessible or non-existing object properties. The purpose of this method is to set extra object data for which you haven’t defined object properties explicitly.

Let’s get back to our example to understand how it works.

<?php class Student { private $data = array(); public function __set($name, $value) { $this->data[$name] = $value; } } $objStudent = new Student(); // __set() called $objStudent->phone = '0491 570 156'; ?>

As you can see in the above example, we’re trying to set the phone property which is non-existent. And thus, the __set() method is called. The first argument of the __set() method is the name of the property which is being accessed and the second argument is the value we’re trying to set.

The __get() Method

In the case of the __set() method example in the previous section, we discussed how to set values for non-existent properties. The __get() method is exactly the opposite of it. The __get() magic method is called when you try to read data from inaccessible or non-existing object properties. The purpose of this method is to provide values to such properties.

Let’s see how it works in action.

<?php class Student { private $data = array(); public function __set($name, $value) { $this->data[$name] = $value; } public function __get($name) { If (isset($this->data[$name])) { return $this->data[$name]; } } } $objStudent = new Student(); // __set() called $objStudent->phone = '0491 570 156'; // __get() called echo $objStudent->phone; ?>

The __toString() Method

The __toString() magic method allows you to define what you would like to display when an object of the class is treated like a string. If you use echo or print on your object, and you haven’t defined the __toString() method, it’ll give an error.

Let’s try to understand it with the following example.

<?php class Student { private $name; private $email; public function __construct($name, $email) { $this->name = $name; $this->email = $email; } public function __toString() { return 'Student name: '.$this->name . '<br>' . 'Student email: '.$this->email; } } $objStudent = new Student('John', '[email protected]'); echo $objStudent; ?>

In the above example, when you echo the $objStudent object, it’ll call the __toString() method. And in that method, you can decide what you would like to display. If you hadn’t defined the __toString() method, this would have resulted in an error!

The __call() and __callStatic() Methods

If __get() and __set() methods are called when you’re dealing with non-existent properties, the __call() method is called when you’re trying to invoke inaccessible methods, the methods that you haven’t defined in your class.

<?php class Student { public function __call($methodName, $arguments) { // $methodName = getStudentDetails // $arguments = array('1') } } $objStudent = new Student(); $objStudent->getStudentDetails(1); ?>

As you can see, we’ve called the method getStudentDetails which is not defined, and thus the __call() magic method is called. The first argument is the name of the method being called and the second argument is an array of arguments that were passed in that method.

The __callStatic() method is very similar to the __call() method with the only exception is that it’s called when you’re trying to invoke inaccessible methods in a static context. So if you’re trying to access any static method which is not defined, the __callStatic() function will be called.

The __isset() and __unset() Methods

The __isset() magic method is called when you call the isset() method on inaccessible or non-existing object properties. Let’s see how it works through an example.

<?php class Student { private $data = array(); public function __isset($name) { return isset($this->data[$name]); } } $objStudent = new Student(); echo isset($objStudent->phone); ?>

In the above example, the phone property is not defined in the class, and thus it’ll call the __isset() method.

On the other hand, the __unset() is a method called when you call the unset() method on inaccessible or non-existing object properties.

The __sleep() and __wakeup() Methods

The __sleep() magic method is different compared to methods that we’ve discussed so far. It’s called when you call the serialize() function on the object. In case of a very large object, you only want to save selected properties during serialization, and clean up the object. The __sleep() method must return an array with the names of all properties of the object that should be serialized.

Again, let’s revise our example to see how it works.

<?php class Student { private $name; private $email; private $phone; private $db_connection_link; public function __construct($name, $email, $phone) { $this->name = $name; $this->email = $email; $this->phone = $phone; } public function __sleep() { return array('name', 'email', 'phone'); } public function __wakeup() { $this->db_connection_link = your_db_connection_function(); } } ?>

In the above example, when you serialize() the Student object, it’ll call the __sleep() method and it’ll only preserve the values of name, email and phone variables.

On the other hand, the use of the __wakeup() magic method is to reestablish any connections and start up tasks when the unserialize() function is called on the object.

The __invoke() Method

The __invoke() magic method is a special method which is called when you try to call an object as if it was a function. Firstly, let’s see how it works and then we’ll see the purpose of this magic method.

<?php class Student { private $name; private $email; public function __construct($name, $email) { $this->name = $name; $this->email = $email; } public function __invoke() { echo 'Student object is called as a function!'; } } $objStudent = new Student('John', '[email protected]'); $objStudent(); ?>

As you can see, the $objStudent object is treated as if it was a function, and as we’ve defined the __invoke() method, it’ll be called instead of giving you an error. The main purpose of the __invoke() method is that if you want to treat your objects as callable, you can implement this method.

The __clone() Method

If you want to duplicate an existing object, you could use the clone keyword to do that. But after cloning, if you want to modify properties of the cloned object, you can define the __clone() magic method in your class.

<?php Class Student_School { } class Student { private $name; private $email; private $object_student_school; public function __construct() { $this->object_student_school = new Student_School(); } public function __clone() { $this->object_student_school = clone $this->object_student_school; } } $objStudentOne = new Student(); $objStudentTwo = clone $objStudentOne; ?>

The issue with the above approach is that it makes a shallow copy of the object while cloning, and thus internal objects of the cloned object will not be cloned.

In the context of the above example, if you wouldn’t have defined the __clone() method, the cloned object, $objStudentTwo, would still point to the same Student_School object referenced by the $objStudentOne object. Thus, by implementing the __clone() method, we make sure that the Student_School object is cloned as well along with the main object.

The __debugInfo() Method

The __debugInfo() magic method is called when you try to dump any object by the var_dump() function. If you haven’t defined this method in your class, it’ll dump all public, private and protected properties. So if you want to restrict the information which is displayed while dumping, you can use this method.

<?php class Student { public $name; private $email; private $ssn; public function __debugInfo() { return array('student_name' => $this->name); } } $objStudent = new Student(); var_dump($objStudent); // object(Student)#1 (1) { ["student_name"]=> NULL } ?>

This method should return an array of key, value pairs which will be displayed when the var_dump() function is called on the object. As you can see, you can completely control what you want to display when the object will be dumped with the var_dump() function.

The __set_state() Method

The __set_state() method is a static method which is used in conjunction with the var_export() function. The var_export() function outputs a structured information about a variable. When you use this function to export classes, you need to define the __set_state() method in your class.

<?php class Student { public $name; private $email; public function __construct($name, $email) { $this->name = $name; $this->email = $email; } public static function __set_state(array $array) { $obj = new Student; $obj->name = $array['name']; $obj->email = $array['email']; return $obj; } } $objStudent = new Student('John','[email protected]'); var_export($objStudent); // Output: Student::__set_state(array( 'name' => 'John', 'email' => '[email protected]', )) ?>

As you can see, the exported string is a valid PHP code and you can use it to restore the original object.

Conclusion

In this article, we’ve gone through all the magic methods available in PHP. For every method, I provided a short but meaningful example which should help you to understand the purpose of it. And I hope you could use this article as a quick reference or a cheatsheet in your day-to-day PHP development.

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rudra0143 · 5 years ago

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isset() Function in PHP | How does isset() Function works in PHP

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Introduction to isset() Function in PHP

The isset() function of PHP usually checks whether variable is set/declared and it is different/other than the NULL. If the variable is unset using the unset() function in PHP then it is no need to be considered at all to set. The isset() function will return the value TRUE only if the variable existed which is not NULL. Otherwise isset()…

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sheilalmartinia · 7 years ago

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How to Set, Get, and Delete WordPress Cookies (like a Pro)

Do you want to learn how to use cookies on your WordPress site? Cookies are a useful tool to store temporary information in user’s browser and then use this information to enhance user experience through personalization and behavioral targeting. In this ultimate guide, we will show you how to set, get, and delete WordPress cookies like a pro.

Note: This is an advanced tutorial. It requires you to have proficient understanding of HTML, CSS, WordPress site, and PHP.

What Are Cookies?

Cookies are plain text files that are created and stored in users browser when they visit a website. Cookies are used to add different features on a website.

Following are some of the common usage of cookies on various websites.

Store and manage user’s login information

Store temporary session information during a users visit

Ecommerce stores use cookies to remember cart items during a user’s visit

Track user activity on a site to offer personalized user experience

and more

As you can see, cookies are highly useful tool for website owners, but they can also be a bit invasive. Recent trends in email marketing, growth hacking, and online marketing as a whole allow websites to set cookies that act as a beacon and can be used to store and even share user activity across websites.

This is why European Union enacted the EU Cookie Law, which requires website owners to declare that they use cookies to store information.

How Cookies are Used in a Typical WordPress Website

By default, WordPress uses cookies to manage logged-in user sessions and authentication. It also uses cookies to remember a user’s name and email address if they fill out a comment form.

However, many WordPress plugins on your website may also set their own cookies. For example, OptinMonster allows you to show different email optin forms to new vs returning visitors, and it does that by using cookies.

If you are using third party services on your website like Google Analytics or Google AdSense, then they may also set cookies on your website.

You can view all website cookies in your browser’s settings. For example, in Google Chrome you need to go to settings and search for ‘content settings’.

Under content settings, you will need to click on ‘Cookies’ to open the cookies settings page.

Next, you need to click on the ‘All cookies and site data’ option.

On the next page, you will see a list of all cookies and site data stored on your browser by all websites you visited.

You can type a website address in the search box, and it will show you the data stored by that website.

Clicking on a single item will show you more details about individual cookies and their contents.

How to Set a Cookie in WordPress

To follow this tutorial, you will need to add code to your theme’s functions.php file or a site-specific plugin. If you haven’t done this before, then please take a look at our guide on how to copy and paste code snippets in WordPress.

First we will use the setcookie() function in PHP. This function accepts the following parameters.

Cookie name

Cookie value

Expire (Optional: sets a time period after which cookie expires)

Path (Optional, by default it will use the site’s root)

Domain (Optional, by default uses your website’s domain)

Secure (Optional, If true then only transfers cookie data via HTTPS)

httponly (Optional, when set true the cookie is only accessible via HTTP and cannot be used by scripts)

Now let’s add a code snippet to your WordPress site. This code stores the exact timestamp when a user visited your website in a cookie.

function wpb_cookies_tutorial1() { $visit_time = date('F j, Y g:i a'); if(!isset($_COOKIE[$wpb_visit_time])) { // set a cookie for 1 year setcookie('wpb_visit_time', $current_time, time()+31556926); } }

You can now visit your website and then check your browser cookies. You will find a cookie with the name wpb_visit_time.

How to Get a Cookie and Use it in WordPress

Now that we have created this cookie that’s stored in user’s browser for 1 year, let’s take a look at how can we use this information on our website.

If you know the name of a cookie, then you can easily call it anywhere in PHP using the $_COOKIE[] variable. Let’s add some code that not only sets the cookie but also uses it to do something on your website.

We have commented the code to show you what each part does. This code uses the information stored in the cookie and outputs it using the shortcode. You can now add shortcode [greet_me] anywhere on your website, and it will show when a user last visited.

Feel free to modify the code to make it more useful for your website. For example, you can show recent posts to returning users and popular posts to new users.

Deleting a Cookie in WordPress

So far we have learned how to set a cookie and use it later in your website. Now let’s take a look at how to delete a cookie.

To delete a cookie, you need to add the following line to your code.

unset($_COOKIE['wpb_visit_time']);

Don’t forget to replace wpb_visit_time with the name of the cookie you are trying to delete.

Let’s put this code in some context using the same sample code we used above. This time we will delete a cookie and set it again with new information.

As you can see, this code deletes the cookie once we have used the information stored inside. Later we set the cookie again with the updated time information.

We hope this article helped you learn how to easily set, get, and delete WordPress cookies. You may also want to see our list of other extremely useful tricks for the WordPress functions file.

If you liked this article, then please subscribe to our YouTube Channel for WordPress video tutorials. You can also find us on Twitter and Facebook.

The post How to Set, Get, and Delete WordPress Cookies (like a Pro) appeared first on WPBeginner.

from WPBeginner http://www.wpbeginner.com/wp-tutorials/how-to-set-get-and-delete-wordpress-cookies-like-a-pro/

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datacouncil11-blog · 8 years ago

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PHP interview questions and Openings for freshers

PHP interview questions and answers for freshers

Welcome !!!. In this section we are providing you some frequently asked PHP Interview Questions which will help you to win interview session easily. Candidates must read this section,Then by heart the questions and answers. Also, review sample answers and advice on how to answer these typical interview questions. PHP is an important part of the web world, and every web developer should have the basic knowledge in PHP.Common PHP interview questions, which should help you become a best PHP codder. We hope you find these questions useful. If you are an interviewer, Take the time to read the common interview questions you will most likely be asked.

For more information about placement and interviews visit us at - https://www.datacouncil.in/

or Walk in to our institute at karvenagar, Pune.

What is PHP?PHP is a server side scripting language commonly used for web applications. PHP has many frameworks and cms for creating websites.Even a non technical person can cretae sites using its CMS.WordPress,osCommerce are the famus CMS of php.It is also an object oriented programming language like java,C-sharp etc.It is very eazy for learning

What is the use of "echo" in php?It is used to print a data in the webpage, Example: , The following code print the text in the webpage

How to include a file to a php page?We can include a file using "include() " or "require()" function with file path as its parameter.

What's the difference between include and require?If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.

require_once(), require(), include().What is difference between them?require() includes and evaluates a specific file, while require_once() does that only if it has not been included before (on the same page). So, require_once() is recommended to use when you want to include a file where you have a lot of functions for example. This way you make sure you don't include the file more times and you will not get the "function re-declared" error.

Differences between GET and POST methods ?We can send 1024 bytes using GET method but POST method can transfer large amount of data and POST is the secure method than GET method .

How to declare an array in php?Eg : var $arr = array('apple', 'grape', 'lemon');

What is the use of 'print' in php?This is not actually a real function, It is a language construct. So you can use with out parentheses with its argument list. Example print('PHP Interview questions'); print 'Job Interview ');

What is use of in_array() function in php ?in_array used to checks if a value exists in an array

What is use of count() function in php ?count() is used to count all elements in an array, or something in an object

What's the difference between include and require?It's how they handle failures. If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.

What is the difference between Session and Cookie?The main difference between sessions and cookies is that sessions are stored on the server, and cookies are stored on the user's computers in the text file format. Cookies can't hold multiple variable while session can hold multiple variables..We can set expiry for a cookie,The session only remains active as long as the browser is open.Users do not have access to the data you stored in Session,Since it is stored in the server.Session is mainly used for login/logout purpose while cookies using for user activity tracking

How to set cookies in PHP?Setcookie("sample", "ram", time()+3600);

How to Retrieve a Cookie Value?eg : echo $_COOKIE["user"];

How to create a session? How to set a value in session ? How to Remove data from a session?Create session : session_start(); Set value into session : $_SESSION['USER_ID']=1; Remove data from a session : unset($_SESSION['USER_ID'];

what types of loops exist in php?for,while,do while and foreach (NB: You should learn its usage)

MYSQL

How to create a mysql connection?mysql_connect(servername,username,password);

How to select a database?mysql_select_db($db_name);

How to execute an sql query? How to fetch its result ?$my_qry = mysql_query("SELECT * FROM `users` WHERE `u_id`='1'; "); $result = mysql_fetch_array($my_qry); echo $result['First_name'];

Write a program using while loop$my_qry = mysql_query("SELECT * FROM `users` WHERE `u_id`='1'; "); while($result = mysql_fetch_array($my_qry)) { echo $result['First_name'.]." "; }

How we can retrieve the data in the result set of MySQL using PHP?

What is the use of explode() function ?Syntax : array explode ( string $delimiter , string $string [, int $limit ] ); This function breaks a string into an array. Each of the array elements is a substring of string formed by splitting it on boundaries formed by the string delimiter.

What is the difference between explode() and split() functions?Split function splits string into array by regular expression. Explode splits a string into array by string.

What is the use of mysql_real_escape_string() function?It is used to escapes special characters in a string for use in an SQL statement

Write down the code for save an uploaded file in php.if ($_FILES["file"]["error"] == 0) { move_uploaded_file($_FILES["file"]["tmp_name"], "upload/" . $_FILES["file"]["name"]); echo "Stored in: " . "upload/" . $_FILES["file"]["name"]; }

How to create a text file in php?$filename = "/home/user/guest/newfile.txt"; $file = fopen( $filename, "w" ); if( $file == false ) { echo ( "Error in opening new file" ); exit(); } fwrite( $file, "This is a simple test\n" ); fclose( $file );

How to strip whitespace (or other characters) from the beginning and end of a string ?The trim() function removes whitespaces or other predefined characters from both sides of a string.

What is the use of header() function in php ?The header() function sends a raw HTTP header to a client browser.Remember that this function must be called before sending the actual out put.For example, You do not print any HTML element before using this function.

How to redirect a page in php?The following code can be used for it, header("Location:index.php");

How stop the execution of a php scrip ?exit() function is used to stop the execution of a page

How to set a page as a home page in a php based site ?index.php is the default name of the home page in php based sites

How to find the length of a string?strlen() function used to find the length of a string

what is the use of rand() in php?It is used to generate random numbers.If called without the arguments it returns a pseudo-random integer between 0 and getrandmax(). If you want a random number between 6 and 12 (inclusive), for example, use rand(6, 12).This function does not generate cryptographically safe values, and should not be used for cryptographic uses. If you want a cryptographically secure value, consider using openssl_random_pseudo_bytes() instead.

what is the use of isset() in php?This function is used to determine if a variable is set and is not NULL

What is the difference between mysql_fetch_array() and mysql_fetch_assoc() ?mysql_fetch_assoc function Fetch a result row as an associative array, While mysql_fetch_array()fetches an associative array, a numeric array, or both

What is mean by an associative array?Associative arrays are arrays that use string keys is called associative arrays.

What is the importance of "method" attribute in a html form?"method" attribute determines how to send the form-data into the server.There are two methods, get and post. The default method is get.This sends the form information by appending it on the URL.Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send.

What is the importance of "action" attribute in a html form?The action attribute determines where to send the form-data in the form submission.

What is the use of "enctype" attribute in a html form?The enctype attribute determines how the form-data should be encoded when submitting it to the server. We need to set enctype as "multipart/form-data" when we are using a form for uploading files

How to create an array of a group of items inside an HTML form ?We can create input fields with same name for "name" attribute with squire bracket at the end of the name of the name attribute, It passes data as an array to PHP. For instance :

Define Object-Oriented MethodologyObject orientation is a software/Web development methodology that is based on the modeling a real world system.An object is the core concept involved in the object orientation. An object is the copy of the real world enity.An object oriented model is a collection of objects and its inter-relationships

How do you define a constant?Using define() directive, like define ("MYCONSTANT",150)

How send email using php?To send email using PHP, you use the mail() function.This mail() function accepts 5 parameters as follows (the last 2 are optional). You need webserver, you can't send email from localhost. eg : mail($to,$subject,$message,$headers);

How to find current date and time?The date() function provides you with a means of retrieving the current date and time, applying the format integer parameters indicated in your script to the timestamp provided or the current local time if no timestamp is given. In simplified terms, passing a time parameter is optional - if you don't, the current timestamp will be used.

Difference between mysql_connect and mysql_pconnect?There is a good page in the php manual on the subject, in short mysql_pconnect() makes a persistent connection to the database which means a SQL link that do not close when the execution of your script ends. mysql_connect()provides only for the databasenewconnection while using mysql_pconnect , the function would first try to find a (persistent) link that's already open with the same host, username and password. If one is found, an identifier for it will be returned instead of opening a new connection... the connection to the SQL server will not be closed when the execution of the script ends. Instead, the link will remain open for future use.

What is the use of "ksort" in php?It is used for sort an array by key in reverse order.

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

What are the encryption techniques in PHPMD5 PHP implements the MD5 hash algorithm using the md5 function, eg : $encrypted_text = md5 ($msg);mcrypt_encrypt :- string mcrypt_encrypt ( string $cipher , string $key , string $data , string $mode [, string $iv ] ); Encrypts plaintext with given parameters

What is the use 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.

How to delete a file from the systemUnlink() deletes the given file from the file system.

How to get the value of current session id?session_id() function returns the session id for the current session.

What are the differences between mysql_fetch_array(), mysql_fetch_object(), mysql_fetch_row()?

What are the different types of errors in PHP ?Here are three basic types of runtime errors in PHP:

what is sql injection ?SQL injection is a malicious code injection technique.It exploiting SQL vulnerabilities in Web applications

What is x+ mode in fopen() used for?Read/Write. Creates a new file. Returns FALSE and an error if file already exists

How to find the position of the first occurrence of a substring in a stringstrpos() is used to find the position of the first occurrence of a substring in a string

What is PEAR?PEAR is a framework and distribution system for reusable PHP components.The project seeks to provide a structured library of code, maintain a system for distributing code and for managing code packages, and promote a standard coding style.PEAR is broken into three classes: PEAR Core Components, PEAR Packages, and PECL Packages. The Core Components include the base classes of PEAR and PEAR_Error, along with database, HTTP, logging, and e-mailing functions. The PEAR Packages include functionality providing for authentication, networking, and file system features, as well as tools for working with XML and HTML templates.

Distinguish between urlencode and urldecode?This method is best when encode a string to used in a query part of a url. it returns a string in which all non-alphanumeric characters except -_. have replece with a percentege(%) sign . the urldecode->Decodes url to encode string as any %and other symbole are decode by the use of the urldecode() function.

What are the different errors in PHP?In PHP, there are three types of runtime errors, they are:Warnings: These are important errors. Example: When we try to include () file which is not available. These errors are showed to the user by default but they will not result in ending the script. Notices: These errors are non-critical and trivial errors that come across while executing the script in PHP. Example: trying to gain access the variable which is not defined. These errors are not showed to the users by default even if the default behavior is changed. Fatal errors: These are critical errors. Example: instantiating an object of a class which does not exist or a non-existent function is called. These errors results in termination of the script immediately and default behavior of PHP is shown to them when they take place. Twelve different error types are used to represent these variations internally.

1. mysql_fetch_row

2. mysql_fetch_array

3. mysql_fetch_object

4. mysql_fetch_assoc

Mysql_fetch_array Fetch a result row as an associative array, a numeric array, or both.

mysql_fetch_object ( resource result ) Returns an object with properties that correspond to the fetched row and moves the internal data pointer ahead. Returns an object with properties that correspond to the fetched row, or FALSE if there are no more rows

mysql_fetch_row() fetches one row of data from the result associated with the specified result identifier. The row is returned as an array. Each result column is stored in an array offset, starting at offset 0.

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.

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