LAMP Architecture

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

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.

Learning PHP

Learning Basics

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

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 BrowserHow PHP Works ends with ; Code blocks are enclosed in { } Comments begin with // or # (Single line) and /* …. */ (For Multi

Line)

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

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

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

Data Types

Boolean Integer Float String Array Object Resource NULL

Assigning & Using Variable Values

<?php

$age = $dob +15;

?> <?php

$today = “Jan 05 2004”;

echo “today is $today “ ;

?>

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) ;

?>

Detecting the Data type

Specialized functions is_bool is_string is_numeric is_float is_int is_null is_array is_object

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($me);//returns NULLecho gettype($me);

?>

Using Operators <?php

$num1 = 101;

$num2 = 5;

$sum = $num1 + $num2;

$diff = $num1 - $num2;

$product = $num1 * $num2;

$quotient = $num1 / num2 ;

$remainder = $num1 % $num2 ;

?>

Using OperatorsOperators What It does

. Concatenation

== Equal to

=== Equal to and of the same type

!== Not Equal to or not of the same type

<> aka != Not Equal to

&& Logical AND

|| Logical OR

XOR Logical XOR

! Logical NOT

++ Increment

-- Decrement

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 );

?>

if() Statement<?php

if (conditional test){ do this;}else{ do this;}?>

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

else{ do this ;} ?>

switch() Statement<?php switch ($country) { case ‘UK’ : $capital = ‘London’; break;

case ‘US’ : $capital = ‘Washington’; break;

case ‘FR’ : $capital = ‘Paris’; break;

default : $capital = ‘Unknown’; break;}?>

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)

for() Loop

<?php

for ($x = 0 ; $x <= 100 ; $x++)

{

echo “$x”;

}

?>

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” );

?>

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

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

Creating Arrays

<?php

$flavors[0] = “Strawberry”;

$flavors[1] = “Grapes”;

OR For Associative Array

$Fruits[red] = “Apple”;

$Fruits[green] = “Grape”;

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”;

Processing Arrays with Loops

<?php$flavors = array("Strawberry", "Grape" ,

"Vanilla" ,"Caramel", "Choclate" ); for($x=0; $x < sizeof($flavors); $x++){ echo “<li> $flavors[$x] “ ;}?>

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

The foreach() Loop

<?php$num = array(10,20,30,40,50,60,70);

foreach($num as $item){ echo "<li> $item "; }?>