Introduction to web and php mysql

Introduction to World Wide Web and basics of PHP
By http://programmerblog.net
By Programmer Blog http://programmerblog.net/

What is Internet and World Wide Web?
 Internet – Global system of interconnected networks
 It is a network of networks that consists of millions of private, public, academic,
business, and government networks of local to global scope.
 Use TCP/IP to serve billions of users worldwide.
 Voice over Internet Protocol (VoIP) and IPTV. Newspaper publishing, blogging, and
web feeds.
 Human interactions through instant messaging, Internet forums, and social
networking sites.
 www – Collection of interconnected documents and other resources
 System of interlinked hypertext documents contained on the Internet.
 http – Hyper Text Transfer Protocol
 Hyperlink (or link) is a reference to a document that the reader can directly follow.
 Hypertext is text displayed with references (hyperlinks) to other text that the reader
can immediately access
 Protocol to transfer hypertext docs from server to client.
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Web Application Development
 Web application development is the process and practice of
developing web applications.
 Request / Response Model
 In HTTP, web browsers or spiders typically act as clients, while an
application running on the computer hosting the web site acts as a server
 Static vs. Dynamic web pages
 Server Side Scripting Languages
 J.S.P, ASP. Net Cold Fusion, Python, PHP

W.A.M.P Installation
 On windows WAMP or XAMPP can be installed
 Web Server – Apache
 Server Side Language – PHP
 DBMS – MySql
 PhpMyAdmin

PHP History
 Rasmus Lerdorf - Creator of PHP language
 PHP - 1995 Collection of Perl/CGI scripts
 PHP/FI was created by Rasmus Lerdorf in 1995, initially as a simple set of Perl
scripts for tracking accesses to his online resume
 PHP/FI - 1997 Form Interpreter
 Rasmus wrote a much larger C implementation, which was able to
communicate with databases, and enabled users to develop simple
dynamic Web applications .
 Personal Home Page / Forms Interpreter
 PHP 3.0 June 1998
 lots of different databases, protocols and APIs,
 Developers joined in and submit new extension modules
 PHP: Hypertext Preprocessor.

PHP History
 PHP 4
 Zend Engine Introduced in 1999
 Support for Web servers
 Object Oriented Programming
 PHP 5
 Zend Engine 2.0
 XML and Web Services
 Object Oriented Support
 Exception Handling
 A lot of new Features

PHP History
PHP 7 – current version on PHP
is latest version of PHP with lot of improvement. Some of
new features are:
1. Speed
2. Type Declaration
3. Return Type Declarations
4. Error Handling
5. Spaceship Operator
6. Null Coalesce Operator
7. Unicode support for emoji and international characters.
8. Constant arrays using define()
9. Anonymous classes
10.Generator delegation

Why PHP ?
 Open Source – Linux – Apache - PHP - MySQL
 One of top 5 most popular languages
 Small – medium – enterprise level applications
 Server Side Scripting
 Command Line
 Desktop Applications (PHP – GTK)
 Available for Windows, Linux, Mac
Many Web Servers – Apache, IIS, nginx, Lighthttpd
 Relational / No SQL Databases MySql, Oracle, MSSQL, mongoDB,
PostgreSql
 Built in Support – Regex, XML and other functions math etc
 Services – LDAP, POP3 and so on

PHP – Online Popular Projects
 PHP
 Facebook - The world’s biggest social networking platform is written in
PHP.
 150 million users and counting, and in my experience, significantly faster
and more stable than competing platforms written in other languages
(e.g. MySpace).
 Yahoo! - formerly the world’s largest search engine. Yahoo! makes use
of PHP.
 You Tube - the world’s biggest video sharing website uses PHP
technology.
 Wikipedia - User contributed web encyclopedia has PHP elements.
 Digg.com
Social news network.
 Sourceforge.org
The world's largest Open Source software development web site.
 Flickr.com
Online photo sharing and storing:

PHP Configuration
PHP.ini
Php configuration file is read when php starts up. Values of different environment
variables can be set in php.ini file. Some of the features are:
 Execution time
 File upload size and so on
 Session paths
 Upload file size
 Short tags
 Error reporting
 Safe mode

PHP Basics: Code Blocks
 Standard Tags: <?php …… ?>
 Short Tags: <?........ ?>
 ASP Tags: <%.....%> (Removed from php 7.0)
 Script Tags
 <script language=“PHP”></script> (Removed from
PHP 7.0)

PHP Basics: Language Constructs
 Constructs are elements that are built-into the
language
 echo
 echo 10;
Every statement ends with semi colon.

PHP Basics: Comments
Single Line Comments -
 // this is a single line comment
 # this is a single line comment
Multi Line Comments - /* ….. */
 /* This is a
Multi line comment
 */

PHP Basics: Data Types
Scalar Data types
 Integer (Signed)
 String
 Floating point
 Boolean
Composite
 Arrays
 Objects

Integer
 echo 10; echo -123;
echo 066; echo 0xFF;
Floating Point
 echo 10.2; echo 0.009;
 echo 2E7; echo 1e2;

String
 echo “ String in double quotes”;
echo ‘ string in single quotes’;
Boolean
 True or False;
Composite Data types
 Arrays , Objects
Null
Resource

PHP Basics: Variables
PHP is a loosely typed language
Variables are storage container in memory
Variables are identified with $ sign
Valid variables:
 [a-zA-Z], numbers, underscores
 Variable variable
 contents of variable to reference a new variable

PHP Basics: Variables
Variables existence
 Isset
Destroying
 unset
Constants
 define(“country", “United States");

PHP Basics: Operators
operators are the catalysts of operations
 Assignment Operators =
 Arithmetic Operators + - / * %
 String Operators .
 Comparison Operators < > <= >= Ternary operator
 Logical Operators && || ! XOR
 Bitwise Operators | & XOR NOT
 Error Control Operators
 Incrementing/Decrementing Operators ++ --
 Typeof

Operators: Increment / Decrement
 $a = 1;
 // Assign the integer 1 to $a
 echo $a++;
 // Outputs 1, $a is now equal to 2
 echo ++$a;
 echo --$a;
 echo $a--;

Operators: Arithmetic Operators
Addition $a = 1 + 3.5;
Subtraction $a = 4 - 2;
Multiplication $a = 8 * 3;
Division $a = 15 / 5;
Modulus $a = 23 % 7;

Concatenation - Assignment Operator
$string = “PHP" . “MySql";
$string2 = “Zend";
$string .= $string2;
echo $string;
Will print: PHP MySql Zend

PHP Basics: Operator Precedence
 $x = 9 + 1 * 10
 Expecting result 100 but getting 19 – Multiplication has higher precedence
Highest Precedence * / %
+ - .
< <= > >=
&&
||
And
Xor
Lowest precedence or

PHP Basics: Escape Sequences
 " Print the next character as a double quote, not a string closer
 ' Print the next character as a single quote, not a string closer
 n Print a new line character (remember our print statements?)
 t Print a tab character
 r Print a carriage return (not used very often)
 $ Print the next character as a dollar, not as part of a variable
 Print the next character as a backslash, not an escape character
 $MyString = "This is an "escaped" string";
$MySingleString = 'This 'will' work';
$MyNonVariable = "I have $marks in my pocket";
$MyNewline = "This ends with a line returnn";
$MyFile = "c:windowssystem32myfile.txt";

PHP Basics: Control Structure -1
 Control structures allow you to control the flow of
your script
if (expression1) {
…
} elseif (expression2) {
…
} else {
…
}

PHP Basics: Control Structure -1
ternary operator
 (condition) ? ’output’ : ’output’;
 echo 10 == $x ? ’Yes’ : ’No’;
 Equivalent in IF-Else
if (10 == $x) {
echo 'Yes';
} else {
echo 'No';
}

Control Structures – Switch statement
 switch (n)
{
case label1:
//code to be executed if n=label1;
break;
case label2:
//code to be executed if n=label2;
break;
default:
// if n is different from both label1 and label2;
}

PHP Basics: Loops
 while - loops through a block of code while a
specified condition is true
 do...while - loops through a block of code once,
and then repeats the loop as long as a specified
condition is true
 for - loops through a block of code a specified
number of times
 foreach - loops through a block of code for each
element in an array

PHP Basics: While Loop
 while (condition)
{
code to be executed;
}
 $i=1;
while($i<=5)
{
echo "The number is " . $i . "<br />";
$i++;
}

PHP Basics: Do While Loop
 do
{
}
while (condition);
 $i=1;
do
{
$i++;
}
while ($i<=5);

PHP Basics: For Loop
 for (init; condition; increment)
{
}
 for ($i=1; $i<=5; $i++)
{
}
 Break
 Causes the loop to stop and program execution to begin at the
statement immediately following the loop.
 Continue
 causes the iteration to be skipped

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Introduction to web and php mysql

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