1. What is PHP?
PHP stands for PHP: Hypertext Preprocessor
PHP is a server-side scripting languagePHP scripts are
executed on the server.
PHP supports many databases (MySQL, Informix, Oracle,
Sybase, Solid, PostgreSQL, Generic ODBC, etc.)
PHP is an open source software (OSS)
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2. Why PHP?
PHP runs on different platforms (Windows, Linux, Unix, etc.)
PHP is compatible with almost all servers used today (Apache, IIS,
etc.)
PHP is FREE to download from the official PHP resource:
www.php.net
PHP is easy to learn
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3. Where to Start?
Install an Apache server on a Windows or Linux machine
Install PHP on a Windows or Linux machine
Install MySQL on a Windows or Linux machine
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4. Download PHP for free here: http://www.php.net/downloads.php
Download MySQL for free here:
http://www.mysql.com/downloads/index.html
Download Apache for free here: http://httpd.apache.org/download.cgi
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5. Basic PHP Syntax
A PHP scripting block always
starts with <?php and
ends with ?>
Example
<?php
…….….
………..
?>
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6. What is a PHP File?
A PHP file normally contains
HTML tags, just like an HTML file
some PHP scripting code
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7. Combining HTML and PHP
<html>
<head>
<title>A PHP script including HTML</title>
</head>
<body>
<b>
"hello world- HTML";
<?php
echo "hello world-PHP";
?>
</b>
</body>
</html>7
8. Comments in PHP
In PHP, we use
// or # to make a single-line comment
/* and */ to make a large comment block.
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10. Variables in PHP
Variables are used for storing a values, like text strings, numbers
or arrays.
When a variable is set it can be used over and over again in your
script
All variables in PHP start with a $ sign symbol.
The correct way of setting a variable in PHP:
$var_name = value;
Eg: $name=“Sunil”;
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12. Variable Naming Rules
A variable name must start with a
letter or an underscore "_"
A variable name can only contain
alpha-numeric characters and
underscores (a-Z, 0-9, and _ )
A variable name should not contain
spaces. If a variable name is more
than one word, it should be separated
with underscore ($my_string), or with
capitalization ($myString)
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13. PHP String
String variables are used for values that contains
character strings.
Example 1:
<?php
$txt="Hello World";
echo $txt;
?>
The output of the code above will be:
Hello World
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14. PHP String
Example 2:
<?php
$txt1="Hello World";
$txt2="1234";
echo $txt1 . " " . $txt2;
?>
The output of the code above will be:
Hello World 1234
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15. PHP String
Example 2:
<?php
echo strlen("Hello world!");
?>
The output of the code above will be:
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15
17. PHP Operators
Comparison Operators
== is equal to 5==8 returns false
!= is not equal 5!=8 returns true
> is greater than 5>8 returns false
< is less than 5<8 returns true
>= is greater than or equal to 5>=8 returns
false
<= is less than or equal to5<=8 returns true
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18. Conditional Statements
If...Else Statement
If you want to execute some code if a condition is true
and another code if a condition is false, use the if....else
statement.
Syntax
if (condition)
code to be executed if condition is true;
else
code to be executed if condition is false;
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21. Conditional Statements
If you want to execute some code if one of several conditions are
true use the elseif statement
Syntax
if (condition)
code to be executed if condition is true;
elseif (condition)
code to be executed if condition is true;
else
code to be executed if condition is false;
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23. PHP Switch Statement
If you want to select one of many blocks of code to be executed,
use the Switch statement.
The switch statement is used to avoid long blocks of if..elseif..else
code.
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24. PHP Switch StatementSyntax
switch (expression)
{
case label1:
code to be executed if expression = label1;
break;
case label2:
code to be executed if expression = label2;
break;
default:
code to be executed
if expression is different from both label1 and label2;
}24
26. Exercise :
Assign values to two variables. Use
comparison operators to test whether
the first value is
The same as the second
Less than the second
Greater than the second
Less than or equal to the second
Print the result of each test to the
browser.
Change the values assigned to your test
variables and run the script again.
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27. PHP Arrays
What is an array?
When working with PHP, sooner or later, you might want to
create many similar variables.
Instead of having many similar variables, you can store the
data as elements in an array.
Each element in the array has its own ID so that it can be
easily accessed.
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28. PHP Arrays : Example 1
<?php
$names[0] = "Peter";
$names[1] = "Quagmire";
$names[2] = "Joe";
echo $names[1] . " and " . $names[2] .
" are ". $names[0] . "'s neighbors";
?>
The code above will output:
Quagmire and Joe are Peter's neighbors
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29. PHP Arrays : Example 2
<?php
$names = array("Peter","Quagmire","Joe");
echo $names[1] . " and " . $names[2] .
" are ". $names[0] . "'s neighbors";
?>
The code above will output:
Quagmire and Joe are Peter's neighbors
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30. Multidimensional Arrays
In a multidimensional array,
each element in the main array can also be an array.
each element in the sub-array can be an array, and so on
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31. Multidimensional Arrays
In a multidimensional array,
each element in the main array can also be an array.
each element in the sub-array can be an array, and so on
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33. PHP Looping
Looping statements in PHP are
used to execute the same block of
code a specified number of times.
In PHP we have the following
looping statements:
while - loops
do...while - loops
for - loops
foreach - loops33
34. The while Statement
The while statement will execute a block of code if and
as long as a condition is true.
Syntax
while (condition)
{
statement 1;
statement 2;
}
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36. do...while Statement
The do...while statement will execute a
block of code at least once - it then will
repeat the loop as long as a condition
is true.
Syntax
do
{
code to be executed;
}
while (condition);
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38. The for Statement
The for statement is used when you know how many
times you want to execute a statement or a list of
statements.
Syntax
for (initialization; condition; increment)
{
code to be executed;
}
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39. The for Statement
Example
.
.
for ($i=1; $i<=5; $i++)
{
echo "Hello World!<br />";
}
.
.
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40. The foreach Statement
The foreach statement is used to loop
through arrays.
For every loop, the value of the current array
element is assigned to $value (and the array
pointer is moved by one) - so on the next
loop, you'll be looking at the next element.
Syntax
foreach (array as value)
{
code to be executed;
}
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41. The foreach Statement
Example
The following example demonstrates a loop
that will print the values of the given array:
<html>
<body>
<?php
$arr=array("one", "two", "three");
foreach ($arr as $value)
{
echo "Value: " . $value . "<br />";
}
?>
</body>
</html>
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42. PHP Functions
A function is a block of code that can be
executed whenever we need it.
Creating PHP functions:
All functions start with the word "function()"
Name the function - It should be possible to
understand what the function does by its name.
The name can start with a letter or underscore
(not a number)
Add a "{" - The function code starts after the
opening curly brace
Insert the function code
Add a "}" - The function is finished by a closing
curly brace
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43. Example 1
A simple function that writes my name when it is called:
<html>
<body>
<?php
function writeMyName()
{
echo “Harvendra Pal Singh";
}
writeMyName();
?>
</body>
</html>
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45. Example 3
The following example will write different first names,
<html>
<body>
<?php
function writeMyName($fname)
{
echo $fname . " .<br />";
}
echo "My name is ";
writeMyName(“Nimal");
echo "My name is ";
writeMyName(“Kamal");
echo "My name is ";
writeMyName(“Amal");
?>
</body>
</html>45
46. Example 4
The following function has two parameters
<html>
<body>
<?php
function writeMyName($fname,$lname)
{
echo $fname . " Refsnes" . $lname . "<br />";
}
echo "My name is ";
writeMyName(“Nimal",“Amarasinghe");
echo "My name is ";
writeMyName(“Kamal",“Perera");
echo "My name is ";
writeMyName(“Amal",“Silva");
?>
</body>
</html>
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47. PHP Functions - Return values
Functions can also be used to return values.
Example
<html>
<body>
<?php
function add($x,$y)
{
$total = $x + $y;
return $total;
}
echo "1 + 16 = " . add(1,16);
?>
</body>
</html>
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48. PHP Forms
The PHP $_GET and $_POST variables are used to
retrieve information from forms, like user input.
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51. PHP $_GET
The $_GET variable is used to collect values from a form
with method="get".
Information sent from a form with the GET method is
visible to everyone (it will be displayed in the browser's
address bar)
It has limits on the amount of information to send (max.
100 characters).
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52. Example
<form action="welcome.php"
method="get">
Name: <input type="text"
name="name" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>
Welcome.php
Welcome <?php echo $_GET["name"]; ?>.<br />
You are <?php echo $_GET["age"]; ?> years old!
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53. Note:
When using the $_GET variable all variable names and
values are displayed in the URL.
So this method should not be used when sending
passwords or other sensitive information!
The HTTP GET method is not suitable on large variable
values; the value cannot exceed 100 characters.
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54. PHP $_POST
The $_POST variable is used to collect values from a
form with method="post".
Information sent from a form with the POST method is
invisible to others and has no limits on the amount of
information to send.
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55. Example
<form action="welcome.php" method="post">
Enter your name: <input type="text" name="name"
/>
Enter your age: <input type="text" name="age" />
<input type="submit" />
</form>
Welcome.php
Welcome <?php echo $_POST["name"]; ?>.<br />
You are <?php echo $_POST["age"]; ?> years old!55
57. Connecting to a MySQL
Database
Before you can access and work with data in a
database, you must create a connection to the
database.
In PHP, this is done with the mysql_connect() function.
Syntax
mysql_connect(servername,username,password
);
servername Optional. Specifies the server to connect to.
Default value is "localhost:3306"
username Optional. Specifies the username to log in with.
Default value is the name of the user that owns
the server process
password Optional. Specifies the password to log in with.
Default is ""
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58. Example
In the following example we store the
connection in a variable ($con). The "die"
part will be executed if the connection
fails:
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
// some code
mysql_close($con);
?>
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59. Create MySQLDatabase and
Tables
To get PHP to execute a MySQL statement we must use
the mysql_query() function.
This function is used to send a query or command to a
MySQL connection.
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60. Example
In the following example we create a database called "my_db":
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
if (mysql_query("CREATE DATABASE my_db",$con))
{
echo "Database created";
}
else
{
echo "Error creating database: " . mysql_error();
}
mysql_close($con);
?>
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61. Create a Table Example
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
// Create table in my_db database
mysql_select_db("my_db", $con);
$sql = "CREATE TABLE person
(
FirstName varchar(15),
LastName varchar(15),
Age int
)";
mysql_query($sql,$con);
mysql_close($con);
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62. Insert new records into a
database table
Example
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
mysql_query("INSERT INTO person (FirstName, LastName, Age)
VALUES ('Peter', 'Griffin', '35')");
mysql_query("INSERT INTO person (FirstName, LastName, Age)
VALUES ('Glenn', 'Quagmire', '33')");
mysql_close($con);
?>
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63. Insert Data From a Form Into
a Database
Example : insert.html
<html>
<body>
<form action="insert.php" method="post">
Firstname: <input type="text" name="firstname" />
Lastname: <input type="text" name="lastname" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>
</body>
</html>
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64. Insert Data From a Form Into
a Database Example : insert.php
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
$sql="INSERT INTO person (FirstName, LastName, Age)
VALUES
('$_POST[firstname]','$_POST[lastname]','$_POST[age]')";
if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
echo "1 record added";
mysql_close($con)
?>
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