Creating Databases applications for the Web Reprise. Basic HTML review, forms Preview: Server side vs client side Classwork: create HTML forms and check query string HW: Review HTML forms

Recall What is a database? A database is made up of …. What interprets the HTML and the JavaScript? What interprets the php? What interprets the SQL? Note: I will repeat myself on this issue!

Postings ???? Please put in comments on the site, NOT just a link –This is a required part of the assignment. –You can edit your post. This is required (points awarded) It is helpful for all of us. It is good training. …..

Caution Chicken and egg problem: what to explain first Try some skipping ahead to motivate explanations.

Hypertext markup language Interpreted by browser on client Displays information Gathers information to send to server by invoking a php script –Most typical way: HTML form – element with extra information in query string (explained soon) HTML5 supports some checking of information put into the form!

Form validation Probably should put in checks anyway: belt and suspenders However, keep in mind that the automatic validation will be done faster than whatever we write in JavaScript.

HTML review Ordinary text plus tags. Tags are singletons or pairs template for all html files:......

HTML examples (old style) My summer vacation Creating an html file requires attention to detail …

HTML: newer style Use styles, including new semantic elements Put as much of the formatting as possible into CSS. Recall: HTML5 logo example (also chance to introduce drawing on canvas) – /html5logoscale.htmlhttp://faculty.purchase.edu/jeanine.meyer/html5 /html5logoscale.html

3-tier logic/implementation model Presentation –content (including structure) HTML5 –format CSS –behavior JavaScript Business logic php Information MySQL

HTML Tables Used to display data from database! Often, [your] PHP code will generate the table tags: tr, td Note: often CSS can be used in place of tables, especially for general layout. –You will see many warnings to avoid tables For tables of data, use tables!

HTML tags referencing files Continue

Reprise Information entered into form will be sent to the file indicated in the action attribute

Structure CLIENT Browser (Firefox): Requests URL SERVER PHP interpreter SERVER DBMS (MySQL) Build HTML page

Notes method=get produces the so-called query string. We can also generate query strings using php OR as direct call –Direct calls can be done for testing method=post sends data another way (via HTTP headers). Benefit is that less is revealed to user. Another benefit is lack of clutter. Older practice in PHP could refer to POST or GET or cookies or variables in the same way. Current practice for PHP is to distinguish these. –Can set up PHP implementation to go back to old, more permissive way Alternative: action="mailto: address"

Query string Name = value pairs –Name is the name of the element –Value is what the person entering data into the form types in Query string will be URL?name1=value1&name2=value2… Blanks will be changed to +. May be other substitutions. –Special characters, including blanks can require special handling at php end.

First Name Last Name Choose one New Media Math/Computer science Other LAS Conservatories Continuing education placeholder

Script referred to by action The php file probably will contain html and code that produces html. –This is reason to know the tags. The php code will be inside special delimiters –REPEAT WARNING: tricky syntax. Much fussing about quotation marks. –more on this later.

After clicking send Browser goes to the file indicated by the action parameter The URL for this is the following (one long string, not split into multiple lines): file:///X|/accepts_data.htm?fname=J eanine&lname=Meyer&category=newmed ia

Second example: file:///X|/accepts_data.htm?fname=J ohn&lname=Smith&category=arts

One more example that doesn't do anything! Generate query string Coffee shop Coffee Hot Cocoa Chai Tall Grand Super Name:

Opened and filled out form

Result (this is okay since I just want to show the query string) This webpage is not found No webpage was found for the web address:file:///C:/Documents%20and%20 Settings/Jeanine/My%20Documents/php/ dummy.html?drink=2.25&sizef=1.5&na me=Jeanine Error 6 (net::ERR_FILE_NOT_FOUND): The file or directory could not be found.

Classwork Create an html document that has a form Open with browser and fill out form Look at query string

NOTE We/you/I can do some testing, such as this, on our own computers (client machine) BUT Most testing will need to be done on the server. –upload work –test –edit/fix/improve, upload again There is an alternative: making a server on our own computers, but it is tedious and only postpones what needs to be done.

phpMyAdmin You can use this for setting up tables, but we also will do this using code. You also can use this for debugging: seeing what is in the tables and, possibly, removing records.

To use phpMyAdmin Need to have requested database access from CSS Download and read the README file. Use First request for id/password, use your regular ( ) id and password –You may need to Second request: use id and pw given in README file

Homework Continue to practice producing HTMLs script with a form with –investigate multiple input elements (e.g., range, radio buttons, check boxes, …) –Use method=get –Use placeholder action=dummy.html –Submit element Test (there will be an error message since dummy.html does not exist!). Look at the query string generated Do postings of php sources if you haven't done so. Comment on others. Sign up for webspace AND database access. –Will start php next class! Does not exist