Open Source Package PHP & MySQL

04/12/23 Technology Park, BDU 1

PHP and MySQLPHP and MySQL


PHP LanguagePHP Language

• A recursive acronym: PHP Hypertext Preprocessor• A scripting language designed for creating

dynamic and data-driven Web pages • PHP is a server-side scripting language; it is

parsed and interpreted on the server side of a Web application and the resulting output is sent to the browser. (VBScript and JavaScript are mostly client-side).

• Designed to work with the MySQL database system, but can also connect to other database systems.


PHP LanguagePHP Language

• PHP and MySQL are open-source; they can be obtained free-of-charge and the source codes are available for development.– www.php.net– www.mysql.com

• You will need to install PHP to work with your MS IIS or Apache Web server.

• PHP and MySQL are becoming increasingly popular in recent years because it is free of charge. Other software packages like Microsoft ASP.NET are expensive for small and medium enterprises.


A Simple PHP ExampleA Simple PHP Example

<HTML><HEAD><TITLE>PHP Example</TITLE></HEAD><BODY><?echo "<b>Welcome</b>"; // print the string here?></BODY></HTML>

• PHP scripts are enclosed by the <?php And ?> tags.– Can simply use <? for the opening tag.

• All PHP statements end with a semicolon (unless it ends the closing tag on the same line)

• Comments can be marked by #, // or /* */

http://147.8.210.143/php/example1.php


Including FilesIncluding Files

• You can include common files (like header, footer, and navigation bars) in PHP.

<? include("header.inc") ?>


Variables in PHPVariables in PHP

• Variable names start with the dollar sign $• You can use letters and underscore for

variable names. • The first character after $ cannot be a

number• Variable names are case-sensitive• For example:

<? $name = "Michael"; ?><? $i = 1; ?>


Variables in PHPVariables in PHP

• The three main types of variables in PHP:– Scalar– Array– Object

• Scalar can be Integer, Double, Boolean, or String• When you assign a value to a variable, its data

type is also assigned.


ArrayArray

• Arrays can be created with integers or strings as keys.

<?php$arr = array("UK" => "London", 12 => 56);

echo $arr["UK"]; // Londonecho $arr[12]; // 56?>


ObjectObject

• Use the class statement to define a class.• Use the new statement to create an object.

<?phpclass test{ function do_something() { echo "Do something"; }}

$my_test = new test;$my_test->do_something();?>


Basic OperatorsBasic Operators

• Assignment/Arithmetic operators= + - * / %++ -- += -= *= /=

• Comparison operators== (equal value)=== (identical value and data type)!= or <>< > <= >=

• Logical operators! && ||


String ConcatenationString Concatenation

• Same as Perl• . concatenate strings• .= concatenate and assign• Example:$word1 = "Play";

$full_string = $word1 . "Station";


String FunctionsString Functions

• There are a lot of string functions in PHP that you can use. For example:– int strlen(string str)– string strtoupper(string str)– string strtolower(string str)– int strcmp(string str1, string str2)– int strcasecmp(string str1, string str2)– string strstr(string src, string target)– int strpos(string src, string target [, int offset])

• You can find them in the PHP manual: http://www.php.net/manual/en/


ConditionsConditions

• boolean variable: TRUE(1) or FALSE(0)

• if (EXPR) { STATEMENTS; } • elseif (EXPR) { STATEMENTS; }• else { STATEMENTS; }• switch-case


LoopsLoops

• while ( EXPR ) { STATEMENTS; }

• do { STATEMENTS; } while (EXPR);

• for ( INIT_EXPR; COND_EXPR; LOOP_EXPR ) { STATEMENTS; }

• foreach (ARRAY as VARIABLE) { STATEMENTS; }

• break, continue


Alternative SyntaxAlternative Syntax

• It is possible to write control statements and loops using the following “colon” format:– <?php

if ($a == 5): echo "A is equal to 5"; endif;

?>


User-defined FunctionsUser-defined Functions

• Functions can be defined using the function keyword.

• <?phpfunction function_name($arg_1, $arg_2, ...){ statements; return $some_value; // optional

}?>


Mixing HTML and PHP CodesMixing HTML and PHP Codes• PHP codes can be easily inserted anywhere in an HTML

page. • You can even mix the codes together, usually to avoid

writing too many “echo” statements with escape characters.

<? if ($i == 1) { ?> <h2>The condition is true</h2> <center><b>$i is 1</b></center><? } else { ?> <h2>The condition is false</h2> <center><b>$i is not 1</b></center><? } ?>

HTMLPHP


Shortcut for Writing EchosShortcut for Writing Echos

• Instead of writing <? echo expression ?>

• You can use the following shortcut<?= expression ?>

• This is useful for inserting expressions and variables quickly into HTML pages.


Working with HTML FormsWorking with HTML Forms

• You can easily get the variables submitted by an HTML form using the following (assume the form input is called “name”:– $_POST['name'] // post method– $_GET['name'] // get method– $name /* easier, but Register Globals must be set to ON in PHP config */


Working with HTML FormsWorking with HTML Forms• It is common to put the form and the results

of different requests in the same file.<HTML><HEAD><TITLE>PHP FORM TEST</TITLE></HEAD><BODY><?if (!isset($name) || $name == "") {?> <FORM METHOD="post"> Your name: <INPUT TYPE="text" NAME="name"> Your age: <INPUT TYPE="text" NAME="age"> <INPUT TYPE="submit"> </FORM><?} else { echo "Your name is $name<BR>"; echo "Your age is $age"; }?></BODY></HTML>

If name is empty or not defined, then show the form

If name is not empty, i.e., when the user has

entered something, then show the results

http://localhost/php/example2.php


PHP and MySQLPHP and MySQL

• PHP is designed to work with the MySQL database. However, it can also connect to other database systems such as Oracle, Sybase, etc., using ODBC.


ExampleExample

<HTML> <BODY> <?php $db = mysql_connect("localhost", "root“,””); mysql_select_db("mydb", $db); $result = mysql_query("SELECT * FROM employees",$db); printf("First Name: %s<br>\n", mysql_result($result,0,"first")); printf("Last Name: %s<br>\n", mysql_result($result,0,"last")); printf("Address: %s<br>\n", mysql_result($result,0,"address")); printf("Position: %s<br>\n",mysql_result($result,0,"position")); mysql_free_result($result);mysql_close($db);?> </BODY> </HTML>


Useful PHP Functions for Useful PHP Functions for MySQLMySQL

• mysql_connect(host, username [,password]);– Connects to a MySQL server on the

specified host using the given username and/or password. Returns a MySQL link identifier on success, or FALSE on failure.

• mysql_select_db(db_name [,resource])– Selects a database from the database

server.



• mysql_query(SQL, resource); – Sends the specified SQL query to the database

specified by the resource identifier. The retrieved data are returned by the function as a MySQL result set.

• mysql_result(result, row [,field]); – Returns the contents of one cell from a MySQL

result set. The field argument can be the field name or the field’s offset.

• mysql_fetch_array(result [,result_type])– Fetch a result row as an associative array, a

numeric array, or both. The result type can take the constants MYSQL_ASSOC, MYSQL_NUM, and MYSQL_BOTH.



• mysql_free_result(result)– Frees the result set

• mysql_close(resource)– Closes the connection to the database.


Error HandlingError Handling

• If there is error in the database connection, you can terminate the current script by using the die function.

• For example: $db = mysql_connect("localhost", "root“, “”) or die("Could not connect : " .

mysql_error());

mysql_select_db("my_database") or die("Could not select database");

$result = mysql_query($query) or die("Query failed");


Example: Looping through the Example: Looping through the CellsCells

<?php/* Connecting, selecting database */$link = mysql_connect("mysql_host", "mysql_user", mysql_password") or die("Could not connect : " . mysql_error());echo "Connected successfully";mysql_select_db("my_database") or die("Could not select database");

/* Performing SQL query */$query = "SELECT * FROM my_table";$result = mysql_query($query) or die("Query failed : " . mysql_error());

/* Printing results in HTML */echo "<table>\n";while ($line = mysql_fetch_array($result, MYSQL_ASSOC)) { echo "\t<tr>\n"; foreach ($line as $col_value) { echo "\t\t<td>$col_value</td>\n"; } echo "\t</tr>\n";}echo "</table>\n";

Loop through each row of the result set

Loop through each element in a row


/* Free resultset */mysql_free_result($result);

/* Closing connection */mysql_close($link);?>

Example: Looping through Example: Looping through the Cellsthe Cells


Thank You

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