LAMP Architecture

1. LAMP Architecture • Typical PHP and MYSQL application development framework follows “LAMP “ Architecture • “LAMP”(Linux , Apache , MySQL and PHP) platform wherein each component plays an important role. • LINUX provides the base OS and Server Environment

2. LAMP Architecture • The Apache Web Server intercepts HTTP requests and either serves them directly or passes them onto the PHP interpreter for execution • The PHP interpreter parses and executes PHP code & returns the results to the webserver • MYSQL RDMS serves as the data storage engine , built connections from PHP Layer for inserting , modifying or retrieving data.

3. Learning PHP Learning Basics

4. Embedding PHP in HTML • There are three possibilities • <?php ….PHP code … ?> • <? …..PHP Code ….. ?> • <% …..PHP Code…. %> • <script language = “php”> ……PHP Code </ script >

5. Sending output to Browser • Echo <?php echo “Hello From PHP “ ; ?> Echo is not a function but a language Construct which sends a String value to the Browser How PHP Works • ends with ; • Code blocks are enclosed in { } • Comments begin with // or # (Single line) and /* …. */ (For Multi Line)

6. To run a Simple PHP File • Make sure that PHP and IIS is installed and properly running • Save Every PHP code with .php extension in directory c:/intepub/wwwroot/php/filename.php • To access the file type in the url bar of IE http://localhost/php/filename.php

7. Language Basics • Variable Names • Begin with a $ sign • First Letter after the $ must be a letter or an underscore • Remaining letters may be numbers or underscores w/o a fixed limit • Case-sensitive • Longer than 30 characters impractical

8. Data Types • PHP is loosely typed language don’t requires declaration of a variable type and automatically convert variable type depending upon the context in which they are used and operations performed on their values • Enables you to check the data type whenever you want to • Supports following data types

9. Data Types • Boolean • Integer • Float • String • Array • Object • Resource • NULL

10. Assigning & Using Variable Values • <?php $age = $dob +15; ?> • <?php $today = “Jan 05 2004”; echo “today is $today “ ; ?>

11. Detecting the Data type • Use of gettype() function <?php $auth = true; $age = 27 ; $name = ‘Bobby’; $temp = 98.6; //returns String echo gettype($name) ; //returns String echo gettype($name) ; //returns Boolean echo gettype($auth) ; //returns integer echo gettype($age) ; //returns double echo gettype($temp) ; ?>

12. Detecting the Data type • Specialized functions • is_bool • is_string • is_numeric • is_float • is_int • is_null • is_array • is_object

13. NULL Values • A Null is typically seen when a variable is initialized but not assigned a value <?php //checks type of un initialized variable //returns NULL echo gettype($me); $me = “Mysterious”; //Check type again //returns STRING echo gettype($me); Unset($me); //returns NULL echo gettype($me); ?>

14. Using Operators • <?php $num1 = 101; $num2 = 5; $sum = $num1 + $num2; $diff = $num1 - $num2; $product = $num1 * $num2; $quotient = $num1 / num2 ; $remainder = $num1 % $num2 ; ?>

15. Using Operators

16. The === Operator <?php //define two variables $str = ’14’; $int = 14; //returns true b/c contains the same value $result = ($str == $int ); //returns false b/c variables are not of the same types $result = ($str === $int ); ?>

17. if() Statement <?php if (conditional test) { do this; } else { do this; } ?>

18. If elseif PHP also provides if-elseif-else() construct <?php if (conditional test) { do this; } elseif (conditional test #1) { do this; } ……….. elseif (conditional test #N) { do this; } else { do this ; } ?>

19. switch() Statement <?php switch ($country) { case ‘UK’ : $capital = ‘London’; break; case ‘US’ : $capital = ‘Washington’; break; case ‘FR’ : $capital = ‘Paris’; break; default : $capital = ‘Unknown’; break; } ?>

20. Other Constructs • Ternary Operator $msg = $dialCount > 10 ? “Cannot connect after 10 attempts “ : “Dialing” ; • while() Loop while( condition is true) { do this; } • do() Loop do { dothis; } while (condition is true)

21. for() Loop <?php for ($x = 0 ; $x <= 100 ; $x++) { echo “$x”; } ?>

22. Using Arrays • Array is a complex variable that allows to store multiple values in a single variable • Can be thought of as a “container” variable which can contain one or more values <?php $flavors = array(‘Strawberry’, ‘Grape’ , “Vanilla” ,’Caramel’, “Choclate” ); ?>

23. Using Arrays • Elements are accessed via index numbers the first index starts at 0 • PHP enables you to replace indices with user defined “ keys” to create a slightly different type of array . Each key is unique and corresponds to a single value. • Keys may be made up of any string characters

24. Using Arrays • $Fruits = array("RED"=> "APPLE" , "YELLOW" =>"BANANA" ,"PURPLE" => "PLUM" , "GREEN"=>"GRAPE"); • This is an array variable containing 4 key value pairs • They are referred to as Hash or Associative Array

25. Creating Arrays <?php $flavors[0] = “Strawberry”; $flavors[1] = “Grapes”; OR For Associative Array $Fruits[red] = “Apple”; $Fruits[green] = “Grape”;

26. Modifying Array Elements • To Add an element to an Array , assign a value using the next available index number or key $flavors[5] = “mango”; OR $flavors [] = “mango”; • To modify an element of an array , assign a new value to the corresponding scalar variable . $flavors[0] = “Blueberry”;

27. Processing Arrays with Loops <?php $flavors = array("Strawberry", "Grape" , "Vanilla" ,"Caramel", "Choclate" ); for($x=0; $x < sizeof($flavors); $x++) { echo “<li> $flavors[$x] “ ; } ?>

28. The foreach() Loop • A new loop type introduced in PHP4.0 for the purpose of iterating over an array • This loop runs once for each element of the array • Unlike a for loop a foreach() loop does not need a counter or a call to sizeof(); it keeps track of it’s position in the array automatically

29. The foreach() Loop <?php $num = array(10,20,30,40,50,60,70); foreach($num as $item) { echo "<li> $item "; } ?>