Digital media technology, autumn 2007

Exercise 4, ( 1.10.-5.10.2007)

1. Company's coffee ring has about 200 employees. There is a web based information system to manage the members of the ring and their coffee consumption. The super user of the system has access on an application that may be used to change the users' status and balance information. In this application the user may specify a search by giving the initial of users' last name of a user. The search produces a list of matching employees. This list contains foe each matching employee the name and the user account name of the employee. .The user account name is used as an identifier for employees. The list is used as a menu for selecting employee records for update. An update may concern the name of the user and three integer values balance data elements. Typically the super users updates about one quarter of the user records in one session..
   Estimate the amount of data transfer and the evaluate the usability of the the following alternatives:

1. A service request is made on the server for both the search and the construction of the update form, and naturally also for the actual update. The pages are build up in the server. A new search has to be activated after each update..
2. Data for the list of employees matching the search condition and the numerals for the update form are fetched from the server in the Ajax way. The whole page is not renewed but only the changing parts (the menu and the update form).
3. The search condition is used to retrieve all personal data needed for the menu and the update. These are shown in a data grid..The super user is able to change the information in the grid and save the row when is has been changed. .
4. There is no search possibility. All the employee records are loaded in the data grid. The update is similar to case c.

You may assume that there is about 100 bytes data for each employee and that name and user account occupy about 80% of this. The header information of service request and response may be assumed to be about 500 bytes each..

2. Find out how data grids (of cases c and d above are typically implemented. (you need not implement one).
3. A simple example of loading a file using Ajax technique was shown in lectures. Improve the example so that text files pertain their original lines and the whole contents of xml-files are shown.. Copy the files in folder http://www.cs.helsinki.fi/u/laine/dime/s07/aesim/. The example file is in Finnish. The first menu option is the Javascript source for the loader function (you should change this), the second one is the css-file, third is an xhtml file and the last one is an xml file.
4. Construct a small page that when loaded checks if Javascript and cookies are allowed and informs at least when they are not allowed..

Exercise to be done during exercise session: Build a skeleton for a php-page on the department's : php-server. The page should show a title, the date and a text you provide as a parameter.. Instructions in Finnish