PHP/MySQL Tutorial Introduction

PHP/MySQL TutorialIntroduction to Database
By:
Prof. Jogeswar Tripathy
NIIS,Bhubaneswar
March 3, 2019
1

What is PHP?
 PHP == „PHP Hypertext Pre-processor‟
 Open-source, server-side scripting language
 Used to generate dynamic web-pages
 PHP scripts reside between reserved PHP tags
 This allows the programmer to embed PHP scripts
within HTML pages
March 3, 20192

What is PHP (cont‟d)
 Interpreted language, scripts are parsed at run-time
rather than compiled beforehand
 Executed on the server-side
 Source-code not visible by client
 „View Source‟ in browsers does not display the PHP
code
 Various built-in functions allow for fast development
 Compatible with many popular databases
March 3, 20193

3 Tier architecture
PHP script
Remote
services
Web Server
(Apache, IIS)
Browser
(IE, FireFox,
Opera)
Desktop
(PC or MAC)
Database
Database
Server
SQL
Client
application
HTTP
HTML
Web Service
tables
DHTML
SMS
vision
touch
voice
SMS system
March 3, 20194

PHP advantages
 Any changes to header or footer only require editing of a
single file.
 This reduces the amount of work necessary for site
maintenance and redesign.
 Helps separate the content and design for easier
maintenance
Page 1
Content
Page 5
Content
Page 3
Content
Page 2
Content
Page 4
Content
Header
Footer
March 3, 20195

What does PHP code look like?
 Structurally similar to C/C++
 Supports procedural and object-oriented paradigm
(to some degree)
 All PHP statements end with a semi-colon
 Each PHP script must be enclosed in the reserved
PHP tag
<?php
…
?>
March 3, 20196

Comments in PHP
 Standard C, C++, and shell comment symbols
// C++ and Java-style comment
# Shell-style comments
/* C-style comments
These can span multiple lines */
March 3, 20197

Variables in PHP
 PHP variables must begin with a “$” sign
 Case-sensitive ($Foo $foo $fOo)
 Global and locally-scoped variables
 Global variables can be used anywhere
 Local variables restricted to a function
or class
 Certain variable names reserved by PHP
 Form variables ($_POST, $_GET)
 Server variables ($_SERVER)
 Etc.
March 3, 20198

Variable usage
<?php
$foo = 25; // Numerical variable
$bar = “Hello”; // String variable
$foo = ($foo * 7); // Multiplies foo by 7
$bar = ($bar * 7); // Invalid expression
?>
March 3, 20199

Echo
 The PHP command „echo‟ is used to
output the parameters passed to it
 The typical usage for this is to send data to
the client‟s web-browser
 Syntax
 echo string arg1 [, string argn...]
March 3, 201910

Echo example
 Notice how echo „5x5=$foo‟ outputs $foo rather
than replacing it with 25
 Strings in single quotes („ ‟) are not interpreted
or evaluated by PHP
 This is true for both variables and character escape-
sequences (such as “n” or “”)
<?php
$foo = 25; // Numerical variable
$bar = “Hello”; // String variable
echo $bar; // Outputs Hello
echo $foo,$bar; // Outputs 25Hello
echo “5x5=”,$foo; // Outputs 5x5=25
echo “5x5=$foo”; // Outputs 5x5=25
echo „5x5=$foo‟; // Outputs 5x5=$foo
?>
March 3, 201911

Arithmetic Operations
 $a - $b // subtraction
 $a * $b // multiplication
 $a / $b // division
 $a += 5 // $a = $a+5
<?php
$a=15;
$b=30;
$total=$a+$b;
Print $total;
Print “<p><h1>$total</h1>”;
// total is 45
?>
March 3, 201912

Concatenation
 Use a period to join strings into one.
<?php
$string1=“Hello”;
$string2=“PHP”;
$string3=$string1 . “ ” . $string2;
Print $string3;
?>
Hello PHP
March 3, 201913
Output

Escaping the Character
 If the string has a set of double quotation
marks that must remain visible, use the
[backslash] before the quotation marks to
ignore and display them.
<?php
$heading=“”Computer Science””;
Print $heading;
?>
“Computer Science”
March 3, 201914
Output

PHP Control Structures
if (expr) statement
<?php
if ($a > $b) {
echo "a is bigger than b";
$b = $a;
}
?>
<?php
if ($a > $b) {
echo "a is greater than b";
} else {
echo "a is NOT greater than b";
}
?>
March 3, 201915

if ($foo == 0) {
echo „The variable foo is equal to 0‟;
}
else if (($foo > 0) && ($foo <= 5)) {
echo „The variable foo is between 1 and 5‟;
}
else {
echo „The variable foo is equal to „.$foo;
}
March 3, 201916

<?php
switch ($i) {
case "apple":
echo "i is apple";
break;
case "bar":
echo "i is bar";
break;
case "cake":
echo "i is cake";
break;
default:
echo „Enter correct option‟;
}
?>
March 3, 201917

Loops
 while (condition) {statements;}
<?php
$count=0;
While($count<3)
{
Print “hello PHP. ”;
$count += 1;
// $count = $count + 1;
// or
// $count++;
?>
hello PHP. hello PHP. hello PHP.
March 3, 201918
Output

Loops
 for (expr1; expr2; expr3)
statement
 <?php
$i = 0;
do {
echo $i;
} while ($i > 0);
?>
March 3, 201919

Loops
 <?php
$arr = array(1, 2, 3, 4);
foreach ($arr as $value) {
echo “$value n”;
}
foreach ($arr as &$value) {
$value = $value * 2;
}
// $arr is now array(2, 4, 6, 8)
unset($value);//break the
reference
?>
March 3, 201920

Loops
 foreach ($arr as $key => $value) {
echo "Key:$key; Value:$value<br />n";
}
 break ends execution of the current for, foreach,
while, do-while or switch structure.
 continue is used within looping structures to skip the
rest of the current loop iteration and continue
execution at the condition evaluation and then the
beginning of the next iteration.
March 3, 201921

Arrays
 An array in PHP is actually an ordered
map which maps values to keys.
 An array can be thought of in many
ways:
 Linearly indexed array , list (vector), hash
table (which is an implementation of a
map), dictionary, collection, stack (LIFO),
queue (FIFO)
March 3, 201922

Arrays
 Kinds of arrays:
 numeric arrays.
 associative arrays.
 multi dimensional arrays.
March 3, 201923

Arrays
 In numeric arrays each key value corresponds to
numeric values.
 They can be divided into two categories
1.automatic numeric array index.
2.manual array numeric index.
automatic numeric array index
<?php
$x=array(1,2,3);
print_r($x);
?>
array(0=>1,1=>2,2=>3)
March 3, 201924
Output :

Arrays
 Manual array numeric index
<?php
$x[2]=10;
$x[3]=50;//$x=array(2=>10,3=>50);
echo $x[2]; echo $x[3];
?>
 Associative arrays
In associated arrays each ID associated with its value
<?php
$x=array(“ab”=>1,”cd”=>2,”xy”=>3);
print_r($x);
?>
March 3, 201925

Arrays
 Multidimensional Arrays-An array contains one or more
arrays
<?php
$z=array(array(10,20,30),array(40,50,60));
print_r($z);
?>
Array ( [0] => Array ( [0] => 10 [1] => 20 [2] => 30 )
[1] => Array ( [0] => 40 [1] => 50 [2] => 60 ) )
March 3, 201926

Arrays
<?php
$x=array(“ab”=>1,array(2,3,4),”cd
”=>8);
print_r($x);
?>
Array ( [“ab”] => 1 [0] => Array ( [0] => 2
[1] => 3 [2] => 4 ) [”cd”] => 8 )
March 3, 201927

Arrays
<?php
$x=array(3=>4,array(2,3,4),5);
print_r($x);
?>
Array ( [3] => 4 [4] => Array ( [0] => 2
[1] => 3 [2] => 4 ) [5] => 5 )
March 3, 201928

Arrays
Array operations
 sort
 ksort
 rsort
 krsort
 array_merge
 array_combine
 array_intersect
March 3, 201929

Date Display
$datedisplay=date(“yyyy/m/d”);
print $datedisplay;
$datedisplay=date(“l, F J, Y”);
print $datedisplay;
Sunday, March 3, 2019
2019/3/3
March 3, 201930
Output :
Output :

Month, Day & Date Format Symbols
M Jan
F January
m 01
n 1
Day of Month d 01
Day of Month J 1
Day of Week l Monday
Day of Week D Mon
March 3, 2019 31

Functions
 Functions MUST be defined before then can be
called
 Function headers are of the format
 Unlike variables, function names are not case
sensitive
function functionName($arg_1, $arg_2, …, $arg_n)
March 3, 201932

Functions example
<?php
// This is a function
function foo($arg_1, $arg_2)
{
$arg_2 = $arg_1 * $arg_2;
return $arg_2;
}
$result_1 = foo(12, 3); // Store
the function
echo $result_1; // Outputs 36
echo foo(12, 3); // Outputs 36
?>
March 3, 201933

Include Files
 include “header.php”;
 include (“footer.php”);
 This inserts files; the code in files will be
inserted into current code.
 require is identical to include except
upon failure it will also produce a fatal
E_COMPILE_ERROR level error. In other
words, it will halt the script whereas
include only emits a warning (E_WARNING)
which allows the script to continue.
March 3, 201934

Include Files
 The include_once statement includes and
evaluates the specified file during the
execution of the script.
 This is a behavior similar to the include
statement, with the only difference being
that if the code from a file has already been
included, it will not be included again.
 The require_once statement is identical to
require except PHP will check if the file has
already been included, and if so, not include
(require) it again
March 3, 201935

PHP - Forms
<?php
if ($_POST["submit"])
echo "<h2>You clicked Submit!</h2>";
else if ($_POST["cancel"])
echo "<h2>You clicked Cancel!</h2>";
?>
<form action="form.php" method="post">
<input type="submit" name="submit"
value="Submit">
<input type="submit" name="cancel"
value="Cancel">
</form>
March 3, 201936

PHP - Forms
<?php
…
$term=$_REQUEST[“sterm”];
…
?>
<form action="form.php" method="post">
<input type=“text" name=“sterm"
value=“<?= $term ?>">
</form>
March 3, 201937

MySQL Connectivity
 mysql_connect()
 The mysql_connect()function opens a non-
persistent MySQL connection.
 This function returns the connection on success, or
FALSE and an error on failure. You can hide the
error output by adding an '@' in front of the
function name.
 Syntax
 mysql_connect(server,user,pwd,newlink,cl
ientflag)
March 3, 201938

MySQL Connectivity
Parameter Description
server Specifies the server to connect to
user Specifies the username to log in with.
pwd Specifies the password to log in with.
newlink If a second call is made to mysql_connect() with the
same arguments, no new connection will be
established; instead, the identifier of the already
opened connection will be returned
clientflag •MYSQL_CLIENT_SSL - Use SSL encryption
•MYSQL_CLIENT_COMPRESS - Use compression protocol
•MYSQL_CLIENT_IGNORE_SPACE - Allow space after
function names
•MYSQL_CLIENT_INTERACTIVE - Allow interactive timeout
seconds of inactivity before closing the connection
March 3, 201939

MySQL Connectivity
 Example:
<?php
$con =
mysql_connect("localhost","mysql_user","mysql
_pwd");
if (!$con){
die('Could not connect: „.mysql_error());
}
echo 'Connected successfully';
mysql_close($con);
?>
March 3, 201940

MySQL Connectivity
 mysql_close()
 The mysql_close() function closes a non-
persistent MySQL connection.
 This function returns TRUE on success, or
FALSE on failure.
 Syntax:
 mysql_close(connection)
connection Specifies the MySQL connection to
close. If not specified, the last
connection opened by
mysql_connect() is used.
March 3, 201941

MySQL Connectivity
 mysql_select_db()
 The mysql_select_db() function sets the active MySQL
database.
 This function returns TRUE on success, or FALSE on
failure.
 Syntax:
 mysql_select_db(database,connection)
database Required. Specifies the database to select.
connection Optional. Specifies the MySQL connection. If
not specified, the last connection opened by
mysql_connect() or mysql_pconnect() is used.
March 3, 201942

MySQL Connectivity
<?php
$con = mysql_connect("localhost", “root",
“admin");
if (!$con){
die('Could not connect: '. mysql_error());
}
$db_selected = mysql_select_db("test_db",
$con);
if (!$db_selected){
die ("Can't use test_db : “.
mysql_error());
}
mysql_close($con);
?>
March 3, 201943

MySQL Connectivity
 mysql_query()
 The mysql_query() function executes a query on a
MySQL database.
 This function returns the query handle for SELECT
queries, TRUE/FALSE for other queries, or FALSE on
failure.
 Syntax
 mysql_query(query,connection)
query Required. Specifies the SQL query to send
(should not end with a semicolon)
connection Optional. Specifies the MySQL connection. If
not specified, the last connection opened by
mysql_connect() or mysql_pconnect() is used.
March 3, 201944

MySQL Connectivity
<?php
$con =
mysql_connect("localhost",”root",”admin");
if (!$con){
die('Could not connect: ' . mysql_error());
}
$sql = "CREATE DATABASE my_db";
if (mysql_query($sql,$con)){
echo "Database my_db created";
}
else{
echo "Error creating database:" .
mysql_error();
}
?>
March 3, 201945

MySQL Connectivity
<?php
$con = mysql_connect("localhost", “root",
“admin");
if (!$con){
die('Could not connect: '. mysql_error());
}
$db_selected = mysql_select_db("test_db", $con);
if (!$db_selected){
die ("Can't use test_db : “. mysql_error());
}
$sql="SELECT * FROM Person where name=„$uname‟";
mysql_query($sql,$con);
mysql_close($con);
?>
March 3, 201946

MySQL Connectivity
 mysql_fetch_array()
 The mysql_fetch_array() function returns a
row from a recordset as an associative array
and/or a numeric array.
 This function gets a row from the
mysql_query() function and returns an array
on success, or FALSE on failure or when
there are no more rows.
 Syntax
 mysql_fetch_array(data,array_type)
March 3, 201947

MySQL Connectivity
data Required. Specifies which data pointer to use. The
data pointer is the result from the mysql_query()
function
array_type Optional. Specifies what kind of array to
return.Possible values:
•MYSQL_ASSOC - Associative array
•MYSQL_NUM - Numeric array
•MYSQL_BOTH - Default. Both associative and
numeric array
March 3, 201948

MySQL Connectivity
 mysql_fetch_row()
 The mysql_fetch_row() function returns a row from
a recordset as a numeric array.
 This function gets a row from the mysql_query()
function and returns an array on success, or FALSE on
failure or when there are no more rows.
 Syntax
 mysql_fetch_row(data)
data Required. Specifies which data pointer to use.
The data pointer is the result from the
mysql_query() function
March 3, 201949

MySQL Connectivity
<?php
echo "<table>";
while ($row = mysql_fetch_row($result)) {
echo "<tr><td>".$row[0]
."</td><td>".$row[1].
"</td><td>".$row[2]."</td><td>".
$row[3]."</td></tr>";
}
echo "</table>";
?>
March 3, 201950

MySQL Connectivity
<?php
echo "<table>";
while ($row = mysql_fetch_array($result))
{
echo "<tr><td>{$row[„ID‟]}
</td><td>{$row[1]}
</td><td>{$row[2]}</td><td>
${row[„mailid‟]}</td></tr>";
}
echo "</table>";
?>
March 3, 201951

Cookies
 The setcookie() function is used to
create cookies. Should be called
before <html> tag.
 setcookie(name, [value], [expire],
[path], [domain], [secure]);
 <?php setcookie("uname", $name,
time()+36000); ?>
 This sets a cookie named "uname" -
that expires after ten hours.
 Either a blank value or a time in
the past makes the cookie expired.
March 3, 201952

Cookies
 To access a cookie, refer to the cookie name
as a variable or use $_COOKIE array. The
isset() checks whether the cookie is set or
not
<html> <body>
<?php
if (isset($uname))// isset($_Cookie[$uname])
echo "Welcome " . $_Cookie[$uname].
"!<br />";
else
echo "You are not logged in!<br />"; ?>
?>
</body> </html>
March 3, 201953

Cookies
Benefit of Cookies :
 Cookies are used for authenticating,
tracking, and maintaining specific
information about users
 Personalised home pages
 Electronic shopping carts.
March 3, 201954

Why use sessions
 A normal HTML website will not pass data
from one page to another
 All information is forgotten when a new
page is loaded
 Many websites need to pass user data from
one page to another
 for tasks like a shopping cart, which requires
data(the user's selected product) to be
remembered from one page to the next
 Using PHP sessions is one solution.
March 3, 201955

 Need for data to stored on the server
 Unique session information for each user
 Transient data, only relevant for short
time
 Data does not contain secret information
 Similar to Cookies, but it is stored on
the server
 More secure, once established, no data
is sent back and forth between the
machines
 Works even if cookies are disabled
 Example: we want to count the number of
“hits” on our web page.
March 3, 201956
When should you use sessions?

Sessions
 The session_start() function is used
to create a session. Should be
called before <html> tag.
<?php
session_start();
?>
March 3, 201957

Sessions
<?php
session_start();
if (!isset($_SESSION['count']))
$_SESSION['count'] = 0;
else
$_SESSION['count']++;
?>
March 3, 201958

Sessions
 session_unregister(´varname´);
unregisters a session variable
 session_destroy() destroys a
session
March 3, 201959

March 3, 201960
Session Example 1
<?php
session_start();
if (!isset($_SESSION["intVar"]) ){
$_SESSION["intVar"] = 1;
} else {
$_SESSION["intVar"]++;
}
echo "<p>In this session you have
accessed this page " .
$_SESSION["intVar"] . "times.</p>";
?>

March 3, 201961
Session Example 2
<?php session_start();?>
<?php
$thisPage = $_SERVER['PHP_SELF'];
$pageNameArray = explode('/', $thisPage);
$pageName = $pageNameArray[count($pageNameArray) - 1];
print "The name of this page is: $pageName<br/>";
$nameItems = explode(„.', $pageName);
$sessionName = $nameItems[0];
print "The session name is $sessionName<br/>";
if (!isset($_SESSION[$sessionName])) {
$_SESSION[$sessionName] = 0;
print "This is the first time you have visited this page<br/>";
}
else {
$_SESSION[$sessionName]++;
}
print "<h1>You have visited this page " . $_SESSION[$sessionName] .
" times</h1>";
?>

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