Unset() function means in php?

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The behavior of unset()  inside of a function can vary depending on what type of variable you are attempting to destroy. If a globalized variable is unset() inside of a function, only the local variable is destroyed. The variable in the calling environment will retain the same value as before unset()  was called. Example <?php function destroy_foo() { global $foo; unset($foo); } $foo = 'bar'; destroy_foo(); echo $foo; ?>
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Error Handling in PHP

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Error handling is the process of catching errors from the program and then taking appropriate action. Before proceeding for error handling you should get to know how many types of errors occurred in PHP. Notices: These are non-critical errors that occurred 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, as you will see, you can change this default behavior. Warnings: These are more serious errors - for example, attempting to use a file (using include() method) which does not exist. By default, these errors are displayed to the user, but they do not result in script termination. Fatal Errors: These are critical errors - for example, creating an…
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Working with Images – PHP

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We need to create an HTML form that allows you to choose the file to be uploaded. Note: please make sure you have form method type is post and enctype=”mutipart/form-data” to to handle file uploading process successfully. HTML Code <form enctype="multipart/form-data" action="process.php" method="POST"> Choose File : <input name="myfile" type="file" /> <input type="submit" value="Upload" /> </form> Now create a PHP file process.php for handling file information <?php // get the uploaded file name $filename= $_FILES['myfile'][‘name’]; // get the file type $filetype= $_FILES['myfile'][‘type’]; // get the file size (in bytes) $filesize= $_FILES['myfile'][‘size’]; // You may put your validations here i.e restrict file size if($filesize>=1000000) { echo “ File is too Large, Maximum file size should be 1 MB”; exit; } // Validation to check if uploaded file is an Image if($filetype !=”image/jpeg”…
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Require () and Include () function in PHP

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The Include() and require() statements are used to insert codes written in other files, in the flow of  execution. The main of using include and require functions to integrate one page code or content into another page. You can maintain usually some repeated functionality in the form of PHP file and finally you can call it wherever you want. See, the following example demonstrates how to integrate a menu content in other pages of PHP. There is a page in menu.php and it can be included in some other pages of the website. Menu.php <a href=”index.php”>Home</a> <a href=”services.php”>Services</a> <a href=”about.php”>About Us</a> <a href=”contact.php”>Contact Us</a> The following page index.php uses above menu.php content. See the below code how it follows <head> <title>My Web page</title> </head> <body> <?php include  “menu.php “; ?> </body> Difference between Include…
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Introduction to Ajax

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Ajax (Asynchronous Java script And XML)  Introduction In Jesse Garrett’s original article that coined the term, it was AJAX. The “X” in AJAX really stands for XML HTTP Request though, and not XML. Jesse later conceded that Ajax should be a word and not an acronym and updated his article to reflect his change in heart. So “Ajax” is the correct casing. As its name implies, Ajax relies primarily on two technologies to work: JavaScript and the XML HTTP Request. Standardization of the browser DOM (Document Object Model) and DHTML also play an important part in Ajax’s success, but for the purposes of our discussion we won’t examine these technologies in depth. How Ajax Works At the heart of Ajax is the ability to communicate with a Web server asynchronously without taking away the…
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Data types in Mysql / Mariadb

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Numeric Data Types: INT (Integer): Int data type represents an integer of normal size. So simply it can used to store numeric value. There are also BIGINT, MEDIUMINT, SMALLINT and TINYINT which represent different range of integer values. DECIMAL: Decimal data type represents numbers with specific floating values. Maximum permitted value is 65 and maximum decimals are 30. There are also FLOAT and DOUBLE to store numeric values with floating point. BOOLEAN:  This data type associates a value 0 with ―”false”, and a value 1 with true. Date and Time Data Types:  DATE: The DATE data type represents a date in “YYYY-MM-DD” format. TIME: The TIME data type represents a time in "HH:MM:SS" format. DATETIME: The DATETIME data type represents date and time in “YYYY-MM-DD HH:MM:SS” format. TIMESTAMP: This data…
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The do-while loop

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Difference Between while and do…while Loop: With a while loop, the condition to be evaluated is tested at the beginning of each loop statement, so if the conditional expression evaluates to false, the loop will never be executed. With a do-while loop, on the other hand, the loop will always be executed once, even if the conditional expression is false, because the condition is evaluated at the end of the loop statement. Example: <?php $i = 1; do { $i++; echo  $i . "<br>"; } while($i <= 3); ?>  Output: 2 3 4
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