PHP-MySQL PHP Basics Content * Introduction to PHP * Installation * PHP Syntax * Saving and Executing PHP page * Comments * Variables * Operators Introduction to PHP * PHP is server side scripting language * Earlier it was Personal Home Page. * Now a days it is PHP: Hypertext Preprocessor * PHP is a powerful tool for making dynamic and interactive web pages. * It was created in 1994 by Rasmus Lerdorf * PHP is a language for creating interactive web sites and is used on over 3.3 million web sites around the world. * PHP files can contain text, HTML tags and scripts * PHP files are returned to the browser as plain HTML. * PHP files have a file extension of ".php" * PHP can run on different platforms (windows, Linux, Unix, etc) * PHP is compatible with almost all servers used today (Apache, IIS, etc.) Installation * You have to install three things - PHP - MySQL - Apache Server * Another Option is to install WAMP( W: Windows A: Apache M: MySQL P: PHP ) * Download WAMP from www.wampserver.com * WAMP is Windows Apache MySQL PHP PHP Syntax * A PHP scripting block always starts with * A PHP scripting block can be placed anywhere in the document. * A PHP file normally contains HTML tags, just like an HTML file, and some PHP scripting code. * The PHP script is executed on the server, and the plain HTML result is sent back to the browser. * Each code line in PHP must end with a semicolon. * There are two basic statements to output text with PHP: echo and print. * The file must have a .php extension. * If the file has a .html extension, the PHP code will not be executed. * Whenever we create a new PHP page, we need to save it in our web servers root directory. * For WAMP it is a folder called www folder and is usually at this location on our hard drive: c:\wamp\www Saving and Executing PHP page <html> <head> <title>My First PHP Page</title> </head> <body> <?php echo "Welcome To PHP"; ?> </body> </html> 1.Save the previous page by the name "demo.php" in the www folder of wamp. 2.Open the browser. 3.Type the url : " http://localhost/demo.php" Comments * Comments: Comments are place in the same fashion as we do in C or C++. You can use single line comment by using //. And multi-line comment using /*...*/ Variables * Variables are used to store constants * These constants could be strings, numbers or arrays. * When a variable is declared, it can be used over and over again in your script. * All variables in PHP start with a $ sign symbol * In PHP, the variable is declared automatically when you use it. * A variable name must start with an alphabet or an underscore "_" * A variable name can only contain alpha-numeric characters and underscores (a-z, A-Z, 0-9, and _ ) * A variable name should not contain spaces. * In PHP, a variable does not need to be declared before adding a value to it. * PHP automatically converts the variable to the correct data type, depending on its value Operators Concatenation Operator * There is only one string operator in PHP, it is the concatenation operator (.) is used to put two string values together. Arithmetic Operators Operator ==> Name ==> Example ==> Result * + ==> Addition ==> $x + $y ==> Sum of $x and $y * - ==> Subtraction ==> $x - $y ==> Difference of $x and $y * * ==> Multiplication ==> $x * $y ==> Product of $x and $y * / ==> Division ==> $x / $y ==> Quotient of $x and $y * % ==> Modulus ==> $x % $y ==> Remainder of $x divided by $y * Operator ==> Name ==> Description * ++$x ==> Pre-increment ==> Increments $x by one, then returns $x * $x++ ==> Post-increment ==> Returns $x, then increments $x by one * --$x ==> Pre-decrement ==> Decrements $x by one, then returns $x * $x-- ==> Post-decrement ==> Returns $x, then decrements $x by one Assignment Operators Assignment ==> Same as... ==> Description * x = y ==> x = y ==> The left operand gets set to the value of the expression on the right * x += y ==> x = x + y ==> Addition * x -= y ==> x = x – y ==> Subtraction * x *= y ==> x = x * y ==> Multiplication * x /= y ==> x = x / y ==> Division * x %= y ==> x = x % y ==> Modulus Relational Operators Operator ==> Name ==> Example ==> Result * == ==> Equal ==> $x == $y ==> True if $x is equal to $y * === ==> Identical ==> $x === $y ==> True if $x is equal to $y, and they are of the same type * != ==> Not equal ==> $x != $y ==> True if $x is not equal to $y * <> ==> Not equal ==> $x <> $y ==> True if $x is not equal to $y * !== ==> Not identical ==> $x !== $y ==> True if $x is not equal to $y, or they are not of the same type * > ==> Greater than ==> $x > $y ==> True if $x is greater than $y * < ==> Less than ==> $x < $y ==> True if $x is less than $y * >= ==> Greater than or equal to ==> $x >= $y ==> True if $x is greater than or equal to $y * <= ==> Less than or equal to ==> $x <= $y ==> True if $x is less than or equal to $y Logical Operators Operator ==> Name ==> Example ==> Result * and ==> And ==> $x and $y ==> True if both $x and $y are true * or ==> Or ==> $x or $y ==> True if either $x or $y is true * xor ==> Xor ==> $x xor $y ==> True if either $x or $y is true, but not both * && ==> And ==> $x && $y ==> True if both $x and $y are true * || ==> Or ==> $x || $y ==> True if either $x or $y is true * ! ==> Not ==> !$x ==> True if $x is not true <<Prev Home Next>>
Friday, July 7, 2017
PHP Basics
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