PHP and MySQL : Server Side Scripting For Web Development

PHP and MySQL : Server Side
Scripting For Web Development
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http://www.edureka.co/php-mysql
Objectives
At the end of this module, you will be able to understand:
 Basics of PHP
 Conditional Logic and Loops
 PHP Form Handling
 PHP Functions
 Object Oriented Concepts
 Implement MySQL with PHP

PHP & MySQL - Overview
 PHP & MySQL is an open-source
 PHP & MySQL are two key components in the open-source LAMP stack
 It is the most appropriate tool for developing dynamic web pages. For example, we can develop informative forums,
chatting platforms, e-commerce shopping carts, CRM solutions, community websites and database driven sites
 PHP with MySQL is a powerful combination showing the real power of Server-Side scripting
 PHP has a wide range of MySQL functions available with the help of a separate module

Benefits of PHP & MySQL
PHP web development means developing websites and dynamic web pages using the versatile and capable server-side
scripting language
CAPABLE
PLATFORM
INDEPENDENT
SUPPORTS ALL
MAJOR WEB
SERVERS
SUPPORTS ALL
MAJOR DATABASES
FREE OF
COST
FASTER
DEVELOPMENTS
LARGE
COMMUNITIES
EASY
PROVEN AND
TRUSTED
SECURE

Intricacies of PHP & MySQL
Dynamic and Weak Typing
Variable Variables
Dynamic Arrays
Dynamic Constants
Dynamic Functions
Dynamic Code
Dynamic Includes
Built-in Functions
Superglobals

What is PHP?
 PHP is the web development language written by and for web developers.
 PHP stands for Hypertext Preprocessor.
 It was originally named as Personal Home Page Tools and later on as Professional Home Page.
 It is a server-side script, which can be embedded in HTML or used as a standalone program script.

Script in PHP
 PHP can be embedded in HTML or can be written as stand-alone program by using special markup tags. They are:
<?php
//PHP code comes here
?>
 We can write PHP script in always available Notepad or get some PHP specific IDE downloaded from internet.
 We can call the file from web browser after saving it using .php extension in webserver directory.

PHP Example
<html>
<head>
<title>PHP Example</title>
<body>
<?php echo “This is my first PHP script."; ?>
</body>
</html>
 The rendered HTML of the above script looks like below:
<html>
<head>
<title>PHP Example</title>
<body>
<p> This is my first PHP script.</p>
</body>
</html>

Environment Setup
 To execute PHP script we need three components to be installed on our computer:
 Web Server - PHP supports many web server, including Apache server and IIS.
 Database - PHP supports many databases. But the extensively used is MySQL.
 PHP Parser - A Parser is required to generate HTML output from PHP code.

PHP Variables
 A variable in any programming language is a name to store a value that can be referenced later as required.
 In PHP, Variables are defined a name preceded by a dollar sign ($). Eg. $firstName, $last_Name etc.
 The type of a variable depends upon the value of its values.
 Equal to (=) operator is used to assign a value to a variable name, on the left-hand side and the value on the
right-hand side.
 In PHP, variables are not required to be declared before assigning a value.
 Data type for a variables is not required to be declared for a variable in PHP. Depending upon the value it is
automatically interpreted.

Decision Making Statements
 Statements that are used to perform certain functions depending on certain conditions are called Decision
making statements as given below:
• If…else statement
• elseif statement
• Switch statement

If-else Statement
<?php
If($user == “Mohit”)
{
print “Hello Mohit.”;
}
else
{
print “You are not Mohit.”;
}
?>

If-elseif Statement
<?php
if($day ==5) {
print(“Five team members. <br>”);
} elseif($day ==4) {
print(“Four team members <br>”);
print(“Three team members <br>”);
print(“Two team members <br>”);
print(“One team members <br>”);
}
?>

Switch Statement
<?php
switch($day)
{
case 3:
print(“Three golden rings <br>”);
break;
case 2:
print(“Two golden rings <br>”);
break;
default:
print(“One golden ring <br>”);
}
?>

Looping Statements
 Following are the various looping statements in PHP:
• For loop
• Foreach loop
• While loop
• Do…while loop

For Statement
 A for statement execution starts with evaluation of initial-expression, which is initialization of counter variable .
 Then evaluation of termination-check is done. if false, the for statement concludes, and if true, the statement
executes.
 Finally, the loop-end-expression is executed and the loop begins again with termination–check.
Example:
<?php
for($counter=1 //initial expression
$counter<4; //termination checks
$counter++ //loop-end expressions) {
print(“$counter<br />”);
}
?>
Result:
1
2
3

Foreach Statement
 We use foreach loop to iterate through arrays and objects.
Example:
<?php
$months = array(“January", “February", “March", “April“,
”May”, ”June”, ”July”, ”August”, ”September”, ”October”,
”November”, ”December”);
foreach ($months as $value) {
echo "$value <br>";
}
?>
Result:
January
February
March
April
May
June
July
August
September
October
November
December

While Statement
 The while loop evaluates the condition expression as Boolean. if true, it executes statements and then starts
again by evaluating condition. If the condition is false, the loop terminates.
Example:
<?php
$count=1;
While($counter<=6)
{
print(“Counter value is $counter <br>”);
$counter = $counter++;
}
?>
Result:
Count value is 1
Count value is 2
Count value is 3
Count value is 4
Count value is 5
Count value is 6

Do-While Statement
 The only difference between while and do-while is that the do-while will execute the statement at least once.
 The statement is executed once, and then the expression is evaluated. If the expression is true, the statement is
repeated until the expression becomes false.
Example:
<?php
$counter=50;
do {
print(“Counter value is $counter. <br>”);
$counter = $counter + 1;
}
While($counter<=10)
?>
Result:
Counter value is 50.

Break Statement
 The break command exits from the inner most loop statements that contain it.
Example:
<?php
for($x=1; $x<10; $x++) {
If($x % 2 !=0) {
break;
print(“$x “);
}
}
?>
Result:
The above code prints nothing because
1 is odd which terminates the for loop
immediately.

Continue Statement
 The continue command skips to the end of the current iteration of the innermost loop that contains it.
Example:
<?php
for($x=1; $x<10; $x++) {
if($x % 2 !=0) {
continue;
}
print(“$x “);
}
?>
Result:
2 4 6 8
Here, the continue statement will skip any
of odd numbers. It will print only the even
numbers.

PHP Forms
 Form is a web page which allows user to enter data.
 Forms contains many elements like text box, text area, checkbox, radio button and submit button
 User enters information in the form elements
 And, the entered information are sent to the server for processing
 Using HTML we can create forms and using PHP we can process form elements
 Let us see an example in the upcoming slides

HTML Form
 See the below example for HTML form with two text boxes and one submit button
<html>
<body>
<form action=“save.php" method="post">
First Name: <input type="text" name=“firstname"><br>
Last Name: <input type="text" name=“lastname"><br>
<input type="submit">
</form>
</body>
</html>
 The user enters the above information and clicks the submit button, the information is sent to a file called
“save.php”

Processing Forms
 The form data is sent to a PHP file for processing
 We can send form data to server using two methods
• GET method
• POST method
 In the previous code, we used POST method to send data. See the below example, to display the submitted data.
To print the values, use the below code in save.php
<?php
Your First name is: <?php echo $_POST["firstname"]; ?>
<br>
Your Lastname is: <?php echo $_POST["lastname"]; ?>
?>

Get Method
 GET method passes argument from one page to the next page.
 It appends the indicated variable name(s) and values(s) to the URL. The value and the page name separated by
question-mark(?)
<form action=“display.php” method=“get”>
Name: <input type=“text” name=“name”><br/>
Email:<input type=“text” name=“email”><br/>
<input type=“submit” value=“submit”>
</form>
<?php
echo “Name: ”.$_GET*‘name’+;
echo “Email: ”.$_GET*‘email’+;
?>

Get Method (Continued)
 Advantage:
• It constructs an actual new and differentiable URL query string. Users can now bookmark this page
 Disadvantage:
• The GET method is not suitable for logins because the username and password are fully visible onscreen as
well as potentially stored in the client browser’s memory as a visited page
• Every GET submission is recorded in the web server log, data set included
• Because the GET method assigns data to a server environment variable, the length of the URL is limited

Post Method
 POST is the preferred method of form submission
 The form data is included in the body of the form when it is forwarding to the processing agent. There will be no
change in the URL
<form action=“display.php” method=“post”>
Name: <input type=“text” name=“name”><br/>
Email:<input type=“text” name=“email”><br/>
<input type=“submit” value=“submit”>
</form>
 POST Method data can be accessed using $_POST variable
<?php
echo “Name: ”.$_POST*‘name’+;
echo “Email: ”.$_POST*‘email’+;
?>

Post Method (Continued)
 Advantages:
• It is more secure than GET because user-entered information is never visible in the URL
• It is much larger limit on the amount of data than can be passed
 Disadvantages:
• The results at a given moment cannot be bookmarked
• This methods can be incompatible with certain firewall setups, which strip the form data as a security
measure

PHP Functions
 A function is a set of codes which are used to perform some specific tasks
 Its main advantage is reusability. Instead of defining a code repeatedly, we can create functions and use them
when needed
 The function will not execute directly when the program loads. We need to call a function
 There are two types of function available in PHP
• Built-in functions - The real power of PHP is its functions. PHP has more than 1000 built-in functions. They
can be invoked directly
• User defined functions - We can also create our own functions. We will discuss about the creation of our
own functions in next slide

PHP Functions Syntax
Example:
function functionName() {
set of code to be executed;
}
 Syntax to call a function:
functionName();
 Rules to follow while naming a function:
• Function names are NOT case-sensitive
• Function name starts with a letter or underscore
• Function name cannot start with numbers

PHP Functions Return Value
 Function can return a value. It will return one value or more than one value using array
 It returns the value using the return keyword. If the return statement is found in the function it will stop
execution and send the value to the callback function.

Function Parameters
 Function parameters are variables passes to the function inside the parentheses. They are declared much like a
typical variable would be:
<?php
// multiply a value by 10 and return it to the caller
function multiply ($value) {
$value = $value * 10;
return $value;
}
$retval= multiply (10);
Print "Return value is $retvaln";
?>

Object Oriented Concepts
 Object Oriented Programming (OOP) is a programming concept used to design our application
• Applications can be of any type
• Web based application
• Window based application
• It is used to write programming in object model structure
 Advantages of Object Oriented Programming
• Re-Usability of your code
• Easy to Maintain
• Good Level of Abstraction

Classes
 Defining PHP Classes
• Class is a user defined data type which includes functions and member variables
• It is used to define object. It is the blueprint of the object
 Class Declaration
• Class is declared using class keyword followed by the name
• A set of braces used to declare variables and functions
• Variables can be declared using var keyword followed by $
<?php
class classname {
var$var1;
var$var2 = "constant text";
function myfunc($arg1, $arg2) {
//function code
}
}
?>

Creating Objects in PHP
 In Object Oriented language, properties are called member variables. And, behaviors are called member
functions
• Once we defined our class, then we can create as many objects using the new operator
• Pen is class, Hero pen, Reynolds etc are called its objects
 Syntax
$objectname= new classname();
Example:
$hero = new Pen;
$reynolds= new Pen;

Calling Member Functions
 After creating objects, we can access our member functions
 We can only access the member function of the class of which we created objects
 Let us see how to access member functions using the objects $hero, $reynolds
Example
Assigning values to the object $hero by accessing its member functions
$hero -> setPrice("100"); //assigns value 100 to price variable
$hero -> setColor("Green"); //assigns value green to color variable
$hero -> setType("Ink Pen"); //assigns value Ink Pen to type variable
$hero -> setWritingcolor(“blue”); //assigns value blue to writing color of the pen

Constructor Functions
 Constructor is a special type of function
 It is automatically invoked when an object is created. So we can use this function for initialization
 To define a constructor, PHP provides a special function called __construct(). We can pass any number of
arguments to this function
 A function can also become a constructor, if it defined by the same name of the class
 Two ways to declare constructors
• __construct() function
• Define function using same class name

Constructor Functions (Continued)
Method 1:
class classname
{
function __construct(p1, p2, ..., pN]){
/* Class initialization code */
}
}
Method 2:
class classname
{
function classname(p1, p2, ..., pN]){
/* Class initialization code */
}
}

Inheritance
 Inheritance is the method of inheriting one class properties to other class
 We can achieve this by using ‘extends’ keyword
Class parentclass
{
//parent class definition
}
Class childclass extends parentclass
{
//child class definition
}

Function Overriding
 Function overriding is nothing but overriding the function of parent class to child class and modify those
functions
 Using overriding, we can alter function definition in child class
 To override, we need to create same function in sub class which it is in base class

class baseclass {
public function one() {
echo “First function”;
}
public function two() {
echo “second function”;
}
}
class childclass extends baseclass {
function two($text) //overriding function2
{
echo "$text ";
}
}
$text = new childclass();
$text->two("Sachin");//it will print Sachin
Function Overriding
 Example:

Access Modifiers
 Access modifiers is nothing but the level of access and the visibility of the member variables and member
functions
 We can use this access modifiers to show or hide data
 We have three access modifiers in PHP
• Private
• Protected
• Public

Final Keyword
 Final is a keyword
 If we define the class as final then we cannot extend the class
 If we declare the method as final we cannot override the method
 Syntax for Defining Function as Final
final public function functioname()
{
//function definition comes here
}
 Syntax for Defining Class as Final
final class classname
{
//class definition comes here
}

Database
 A database is a unique application that organizes a group of data
 Each database application has one or more APIs for creating, managing, accessing, searching and duplicating the
data it holds
 Hence, the data can easily be accessed, managed, and updated

MySQL Introduction
 MySQL is a database system which is used on the web and runs on the server
 It uses standard SQL
 It is very fast, reliable and easy to use and also it is ideal for both small and large applications

MySQL Connection
 Using PHP Script
• Using mysql_connect() function we can open a database connection
• This function requires five parameters and all are optional
 Syntax
mysql_connect(server,user,pass,new_link,client_flag);

MySQL Disconnect
 Using PHP Script
• Using mysql_close() function we can disconnect from MySQL server
• This function takes single parameter
 Syntax
mysql_close(resource $link_identifier);
 If we did not specify any parameter then the last opened database is closed

Execute MySQL Queries
 Using PHP function mysql_query() we can run a MySQL query.
 This function needs two parameters and returns Boolean value
 Function Syntax
mysql_query(sql_query, connection);
 First parameter is mandatory. sql_query parameter is mandatory. It specifies the original query to be executed
 The second parameter is optional. It is the connection parameter. If we did not specified, it takes the last opened
connection
 Consider we are going to create a database ‘student_details’ to store student information

Fetching Data
 Select Query
• Data Manipulation –Select Query
• Select statement is used to fetch data from the database
• Fetching data can be simple queries or complex queries
 To select data using PHP script, we can use mysql_query() function
• Write the select query inside the mysql_query() function
• This function is used to execute MySQL queries
• To fetch the selected data using select query we can use two functions
mysql_fetch_array()
mysql_fetch_assoc()

Questions
Slide 50 http://www.edureka.co/php-mysqlTwitter @edurekaIN, Facebook /edurekaIN, use #AskEdureka for Questions

Course Topics
 Module 1
» PHP Basics and Conditional Logic
 Module 2
» Functions and Error Handling
 Module 3
» Object Oriented Programming
 Module 4
» MySQL Installation and Basics
 Module 5
» Advance Queries and Data Manipulation
using PHP
Module 6
» MVC Infrastructure Basics & Introduction to
CakePHP
Module 7
» CakePHP Controller, Views and Layout
 Module 8
» Models and Database Interaction in CakePHP
 Module 9
» Creating Dynamic Forms using CakePHP Html
Helpers
 Module 10
» Using MVC & CakePHP to develop a website

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Module Wise Quiz
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PHP and MySQL : Server Side Scripting For Web Development

PHP and MySQL : Server Side Scripting For Web Development

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