ProductReview Example

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Revision as of 21:57, 10 January 2008 by Jka (talk | contribs) (hmm. this is a 4GL language. let's skip the coding in the example :P)
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ProductReview Example page under construction

Functionality

This example demonstrates how to create a AJAX solution using Visual DataFlex

The overall goal is to be able to see what users think about a particular item . As an added benefit - users can also share information about where to buy the particular items.


To accomplish this, then users should be able to:

  • login
  • choose an item from a list (use a AJAX Lookup List )
  • enter information about a known item ( AJAX Form )
    • supply information about the place where an item was bought.
  • supply a rating of an item
  • Overview supplied ratings from other users


The system will implemented as a web application, Using the AJAX Library and having a datamodel Using DataDictionaries .

Data model Using DataDictionaries

Table layout

We want to store information about users, places, purchases and known items. A user should be either a normal user or an administrator. The other tables should hold sufficient information about the items purchased and how the users liked them.

Create these tables in the database builder and create the associated data dictionaries .

The following data dictionaries should now be available:

  • Item_DataDictionary
  • Place_DataDictionary
  • Purchase_DataDictionary
  • Rating_DataDictionary
  • UserInfo_DataDictionary

Application design Using the AJAX Library

AJAX WebService Object

Create a AJAX WebService Object to call from the clientside VDF Ajax lib. This webservice will be responsible for handling the serverside calls.

this is the point of entry on the serverside (where information will be extracted from)

AJAX Session management

  • UserLogin: checking if the supplied password is correct. Use UserInfo_DD
  • HasRights: does the logged in user have the rights to perform the chosen function. Use UserInfo_DD

Using AJAX Web Browser Objects

  • item.wo : handling information about items.
  • userinfo.wo : handling information about users
  • place.wo: handling info about places
  • purchase.wo: handle information about places
  • rating.wo: handle information about ratings

The Web Object should use the corresponding data dictionaries

Creating the frontend logic

The web markup should be designed around forms, that evolve around the web objects.

Version 1.1 of the AJAX Library has wizards to create most of this functionality.

  • Rating.asp: a list of items with detailed ratings. show details about related users and items.
  • RateItem.asp: a form to supply rating information about a particular item ( AJAX Form )
  • Place.asp: information about a place where items can be bought ( AJAX Form )
  • Purchases.asp: information about what items users has bought at what place ( AJAX Form )

Implementation