Creating Databases for Web applications

1
Creating Databases for Web applications

• Server side vs client side
• PHP basics
• Homework Get your own versions of sending email
  working both html and Flash!

2
PHP

• php files are interpreted by/on/at the server.
• One or more of the following happens
• php interface to operating system is used to do
  things such as interact with databases OR files
  OR email
• HTML is produced (and sent to the client)
• cookie is set and/or accessed

3
Structure
CLIENT Browser (Firefox) Requests URL
SERVER PHP interpreter
SERVER DBMS (MySQL)
Build HTML page
4
Mechanics in php script

• Need to distinguish html versus php
• Common task will be to generate a string (aka
  character string) made up of html you know ahead
  of time and html generated from variables.

5
phpinfo script

• PHP info test
• echo phpinfo()
• ?

6
Variables

• Concept in all computing
• Variable 'is' a name that holds a value. Can be
  used in place of a literal value. The value can
  vary over use
• PHP variable names begin with , no spaces,
  avoid punctuation except for _
• Rule long enough for you to remember what it is
  used for and short enough to type.

7
php example

• Test
• Welcome to the store
• .
• Print("New Products")
• Print( "
  "newproduct1name)
• ?

Variable set used
8
php variables within strings

• For all php variables, you can put the variable
  name in a string
• print("The name input was fname")
• php figures out that fname is a variable and
  gets its value.
• NOTE out of habit in using other programming
  languages, sometimes I don't do thatprint ("The
  name input was " . fname)
• NOTE the string concatenation operator is .
• Caution SQL often requires a single quotation
  mark

9
Form data in php

• Built-in functions
• _GET' '
• _PUT' '
• If you want to NOT distinguish (considered less
  secure)
• _REQUEST' '

Name in form
10
Checking if a form variable has been set

• Common situation to check if this is first time
• saywhich_at__GET'saywhich'

Prevents error if no value exists
11
random

• rand (a, b) returns a pseudo-random choice from a
  to b, inclusive
• choicerand(0, sizeOf(states)-1)
• The arrays in php (like JavaScript and
  ActionScript) start indexing at zero.

12
Overview

• Useful to think in terms of 3 language domains
  (my terminology)
• client side browser (interpreter of html)
• server side interpreter of asp/JavaScript or php
• (There is another level here for the operating
  system, but this is what the asp objects and the
  php built-in functions variables provide.)
• database interpreter of SQL (by Access or MySQL)

13
Warnings

• Applicable to php and other languages
• To output quotation marks in the HTML, you may
  use single quotes or 'escape' double quotation
  marks
• print ("")
• Response.Write("")
• SQL statements require quotation marks around
  values in certain cases.
• SQL statements use a single equals sign () for
  checking for equality. asp/JavaScript and php
  use in IF statements.

14
php file for sending email

• Note this file can be used from HTML and from
  Flash / ActionScript
• Must execute on server
• Could use post or get or _REQUEST
• This is what is used in Catching Bo

15
sendemail.php

• to _POST'to'
• subject _POST'subject'
• body _POST'body'
• headers "From " . _POST'from'
• if (mail(to, subject, body,headers))
• echo("Your message was sent")
• else
• echo("There was a problem.")
• / message is send even if email(s) not good! /
• ?

16
Extra credit possibility

• Figure out how to get an error
• Note the use of mail is an asynchronous
  operation initiated from php (sent to operating
  system on the server)

17
Look at Flash

• Download source of Catching Bo
• http//newmedia.purchase.edu/Jeanine/as30/chasebo
  thedogemaila.fla

18
Look at html

• http//newmedia.purchase.edu/Jeanine/db/htmlemail
  .html
• Note use of textarea element for multiline input

19
HTML

• Send email
• From
  
• To
  
• Subject
  /
  
• Body

20
Homework

• Implement your versions of BOTH the HTML and the
  Flash for sending email
• Note need to upload the sendemail.php file and
  the .html file and the swf and html file
  published from FLASH