1. Introduction to Database

2. What is PHP? PHP == ‘PHP Hypertext Preprocessor’ 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

3. 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

4. 3(+1) Tier architecture PHP script Remote services Web Server (Apache, IIS) Browser (IE, FireFox, Opera) Desktop (PC or MAC) Database Server SQL Client application HTTP HTML Web Service tables DHTML SMS vision touch voice SMS system

5. PHP advantage 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

6. 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 … ?>

7. 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 */

8. 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.

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

10. 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...]

11. 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 ?>

12. 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 “ $total ”; // total is 45 ?>

13. Concatenation Use a period to join strings into one. <?php $string1=“Hello”; $string2=“PHP”; $string3=$string1. “ ”. $string2; Print $string3; ?> Hello PHP

14. 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”

15. PHP Control Structures if (expr) statement $b) { echo "a is bigger than b"; $b = $a; } ?> $b) { echo "a is greater than b"; } else { echo "a is NOT greater than b"; } ?>

16. PHP Control Structures 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; }

17. PHP Control Structures <?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’; } ?>

18. 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.

19. Loops for (expr1; expr2; expr3) statement 0); ?>

20. 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 ?>

21. Loops foreach ($arr as $key => $value) { echo "Key:$key; Value:$value \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.

22. 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)

23. Arrays Kinds of arrays: numeric arrays. associative arrays. multi dimensional arrays.

24. 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); ?> o/p: array(0=>1,1=>2,2=>3)

25. 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); ?>

26. 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 ) )

27. 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 )

28. 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 )

29. Arrays Array operations sort ksort rsort krsort array_merge array_combine array_intersect

30. Date Display $datedisplay=date(“yyyy/m/d”); print $datedisplay; $datedisplay=date(“l, F J, Y”); print $datedisplay; Wednesday, April 1, 2009 2009/4/1

31. Month, Day & Date Format Symbols MJan FJanuary m01 n1 Day of Monthd01 Day of MonthJ1 Day of WeeklMonday Day of WeekDMon

32. 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)

33. 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 ?>

34. 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.

35. 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

36. PHP - Forms <?php if ($_POST["submit"]) echo " You clicked Submit! "; else if ($_POST["cancel"]) echo " You clicked Cancel! "; ?>

37. PHP - Forms <?php … $term=$_REQUEST[“sterm”]; … ?> ">

38. 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,client flag)

39. MySQL Connectivity ParameterDescription serverSpecifies the server to connect to userSpecifies the username to log in with. pwd Specifies the password to log in with. newlinkIf 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

40. MySQL Connectivity Example: <?php $con = mysql_connect("localhost","mysql_user","mysq l_pwd"); if (!$con){ die('Could not connect: ‘.mysql_error()); } echo 'Connected successfully'; mysql_close($con); ?>

41. 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) ParameterDescription connectionSpecifies the MySQL connection to close. If not specified, the last connection opened by mysql_connect() is used.

42. 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) ParameterDescription databaseRequired. Specifies the database to select. connectionOptional. Specifies the MySQL connection. If not specified, the last connection opened by mysql_connect() or mysql_pconnect() is used.

43. 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); ?>

44. 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) ParameterDescription queryRequired. Specifies the SQL query to send (should not end with a semicolon) connectionOptional. Specifies the MySQL connection. If not specified, the last connection opened by mysql_connect() or mysql_pconnect() is used.

45. 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(); } ?>

46. 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); ?>

47. 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)

48. MySQL Connectivity ParameterDescription dataRequired. Specifies which data pointer to use. The data pointer is the result from the mysql_query() function array_typeOptional. 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

49. 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) ParameterDescription dataRequired. Specifies which data pointer to use. The data pointer is the result from the mysql_query() function

50. MySQL Connectivity <?php echo " "; while ($row = mysql_fetch_row($result)) { echo " ".$row[0]." ".$row[1]. " ".$row[2]." ". $row[3]." "; } echo " "; ?>

51. MySQL Connectivity <?php echo " "; while ($row = mysql_fetch_array($result)) { echo " {$row[‘ID’]} {$row[1]} {$row[2]} ${row[‘mailid’]} "; } echo " "; ?>

52. Cookies The setcookie() function is used to create cookies. Should be called before tag. setcookie(name, [value], [expire], [path], [domain], [secure]); 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.

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

54. Cookies Benefit of Cookies Cookies are used for authenticating, tracking, and maintaining specific information about users Personolised home pages Electronic shopping carts.

55. 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.

56. Sessions The session_start() function is used to create a session. Should be called before tag. <?php session_start(); ?>

57. Sessions <?php session_start(); if (!isset($_SESSION['count'])) $_SESSION['count'] = 0; else $_SESSION['count']++; ?>

58. Sessions session_unregister(´varname´); unregisters a session variable session_destroy() destroys a session