Introduction to PHP and PostgreSQL

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.
• lthtmlgt
• ltheadgt
• lttitlegtExamplelt/titlegt
• lt/headgt
• ltbodygt
• lt?php echo "Hi, I'm a PHP script!" ?gt
• lt/bodygt
• lt/htmlgt
• 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
• lthtmlgt
• ltheadgt
• lttitlegtPHP Testlt/titlegt
• lt/headgt
• ltbodygt
• lt?php echo "ltpgtHello Worldlt/pgt" ?gt
• lt/bodygt
• lt/htmlgt
• 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
• lthtmlgt
• ltheadgt
• lttitlegtPHP Testlt/titlegt
• lt/headgt
• ltbodygt
• lt?php echo _SERVER"HTTP_USER_AGENT" ?gt
• lt/bodygt
• lt/htmlgt (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
• lt?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
• ?gt

10
Arrays

• created by the array() language-construct
• takes a certain number of comma-separated key gt
  value pairs
• lt?php
• arr array("foo" gt "bar", 12 gt true)
• echo arr"foo" // bar
• echo arr12 // 1
• ?gt (see it here)

11
Arrays (cont.)

• lt?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 gt value)
  unset(arrayi)
• 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)
• ?gt (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
• ltform action"foo.php" method"POST"gt
• Name ltinput type"text" name"username"gtltbrgt
  Email ltinput type"text" name"email"gtltbrgt
  ltinput type"submit" name"submit" value"Submit
  me!"gt
• lt/formgt

13
Forms foo.php

• lt?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 ?gt (see result here)

14
Another forms example

• info_form.php
• ltform actionshow_answers.php method"POST"gt
• Your name ltinput type"text" name"name" /gt
• Your age ltinput type"text" name"age" /gt
• ltinput type"submit"gt
• lt/formgt
• show_answers.php
• Hi
• lt?php echo _POST"name" ?gt.
• You are lt?php echo _POST"age" ?gt 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)

• lthtmlgt
• ltbodygt
• lt?php
• db pg_connect(dbnamesam usersam
  passwordiam")
• or die(Couldnt Connect .pg_last_error(db))
  
• querySELECT FROM employees
• result pg_query(db,query)
• or
• die(Error in query query..pg_last_error(db)
  )
• rows pg_num_rows(result)
• if (rows gt 0)
• for (i0 iltrows i)
• my_row pg_fetch_array(result, i,
  PGSQL_ASSOC)
• printf("First Name
  s",my_rowfirst)
• printf("Last Name s", my_rowlast)
  
• printf("Address s", my_rowaddress)
• printf("Position s",my_row"position)
  
• printf(\n)

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