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Introduction to PHP and PostgreSQL

Introduction to PHP and PostgreSQL. CSC 436 – Fall 2008 Slides based on PHP manual “Getting Started” from http://www.php.net/tut.php. PHP - Overview. Introduction Tutorial Installation PostgreSQL with PHP Extended example. Introduction.

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Introduction to PHP and PostgreSQL

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  1. Introduction to PHP and PostgreSQL CSC 436 – Fall 2008 Slides based on PHP manual “Getting Started” from http://www.php.net/tut.php

  2. PHP - Overview • Introduction • Tutorial • Installation • PostgreSQL with PHP • Extended example

  3. Introduction • PHP (recursive acronym for "PHP: Hypertext Preprocessor") • widely-used Open Source general-purpose scripting language • especially suited for Web development • can be embedded into HTML. <html> <head> <title>Example</title> </head> <body> <?php echo "Hi, I'm a PHP script!"; ?> </body> </html> • See this example here:

  4. What can PHP do? • Server-side scripting • most traditional and main target field • need three things to make this work • PHP parser (CGI or server module) • webserver – with connected PHP installation • web browser • Command line scripting • PHP script to run it without any server or browser • need the PHP parser to use it this way • Writing client-side GUI applications • not the best language to write windowing applications • use PHP-GTK to write such programs

  5. Tutorial • What do I need? • Your first PHP-enabled page • Something Useful • Dealing with Forms • What's next?

  6. What do I need? • Assume that your server has support for PHP activated and that all files ending in .php are handled by PHP • Create your .php files and put them in your web directory and the server will magically parse them for you • No need to compile anything • Develop locally • install a web server, such as Apache • install PHP • install a database as well, such as PostgreSQL.

  7. First PHP-enabled page • Create a file named hello.php • Put it in your web servers directory <html> <head> <title>PHP Test</title> </head> <body> <?php echo "<p>Hello World</p>"; ?> </body> </html> • Use your browser to access the file

  8. Something useful • check what sort of browser the person viewing the page is using • check the user agent string that the browser sends as part of its HTTP request • stored in a variable • always start with a dollar-sign in PHP • $_SERVER["HTTP_USER_AGENT"]. • $_SERVER is a special reserved PHP variable that contains all web server information <html> <head> <title>PHP Test</title> </head> <body> <?php echo $_SERVER["HTTP_USER_AGENT"]; ?> </body> </html> (see this file)

  9. Variables • Variables represented by a dollar sign followed by the name of the variable • name is case-sensitive. • name starts with a letter or underscore, followed by any number of letters, numbers, or underscores • type is assigned by value <?php $var = "Bob"; $Var = "Joe"; echo "$var, $Var"; // outputs "Bob, Joe" $x = 1; $x = ‘abc’; // type can change if value changes $4site = 'not yet'; // invalid; starts with a number $_4site = 'not yet'; // valid; starts with an underscore ?>

  10. Arrays • created by the array() language-construct • takes a certain number of comma-separated key => value pairs <?php $arr = array("foo" => "bar", 12 => true); echo $arr["foo"]; // bar echo $arr[12]; // 1 ?> (see it here)

  11. Arrays (cont.) <?php // Create a simple array. $array = array(1, 2, 3, 4, 5); print_r($array); // Now delete every item, but leave the array // itself intact: foreach ($array as $i => $value) { unset($array[$i]); } print_r($array); // Append an item (note that the new key is 5, // instead of 0 as you might expect). $array[] = 6; print_r($array); // Re-index: $array = array_values($array); $array[] = 7; print_r($array); ?> (see result here)

  12. Dealing with forms • HTML Forms (GET and POST) • form is submitted to a PHP script • information from that form is automatically made available to the script • forms.php <form action="foo.php" method="POST"> Name: <input type="text" name="username"><br> Email: <input type="text" name="email"><br> <input type="submit" name="submit" value="Submit me!"> </form>

  13. Forms – foo.php <?php // Available since PHP 4.1.0 print $_POST['username']; print $_REQUEST['username']; import_request_variables('p', 'p_'); print $p_username; // Available since PHP 3. As of PHP 5.0.0, these long // predefined variables can be disabled with the // register_long_arrays directive. print $HTTP_POST_VARS['username']; // Available if the PHP directive register_globals = on. // As of PHP 4.2.0 the default value of // register_globals = off. // Using/relying on this method is not preferred. print $username; ?> (see result here)

  14. Another forms example • info_form.php <form action=“show_answers.php” method="POST"> Your name: <input type="text" name="name" /> Your age: <input type="text" name="age" /> <input type="submit"> </form> • show_answers.php Hi <?php echo $_POST["name"]; ?>. You are <?php echo $_POST["age"]; ?> years old. (see results here)

  15. Installation • PHP is installed on the Linux servers in the CSC department • You can install it on your own machine if you want • Refer to the PHP manual for instructions on installation http://www.php.net/manual/en/install.php

  16. PosgreSQL with PHP • Assume the following database table and data: CREATE TABLE employees ( id tinyint(4) DEFAULT '0' NOT NULL AUTO_INCREMENT, first varchar(20), last varchar(20), address varchar(255), position varchar(50), PRIMARY KEY (id), UNIQUE id (id)); INSERT INTO employees VALUES (1,'Bob','Smith','128 Here St, Cityname', 'Marketing Manager'); INSERT INTO employees VALUES (2,'John','Roberts','45 There St ,Townville', 'Telephonist'); INSERT INTO employees VALUES (3,'Brad','Johnson','1/34 Nowhere Blvd, Snowston', 'Doorman');

  17. PostgreSQL Example (cont) <html> <body> <?php $db = pg_connect(“dbname=sam user=sam password=iam") or die(“Couldn’t Connect: “.pg_last_error($db)); $query=“SELECT * FROM employees”; $result = pg_query($db,$query) or die(“Error in query: $query.”.pg_last_error($db)); $rows = pg_num_rows($result); if ($rows > 0) { for ($i=0; $i<$rows; $i++){ $my_row = pg_fetch_array($result, $i, PGSQL_ASSOC); printf("First Name: %s",$my_row[“first”]); printf("Last Name: %s", $my_row[“last“]); printf("Address: %s", $my_row[“address“]); printf("Position: %s",$my_row["position“]); printf(“\n”); } } pg_close($db); ?> </body> </html>

  18. Extended Example – Toy Catalog • Toy Catalog – as described in class • Assume database tables created • Assume data inserted into data • Start with html form page

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