Grids, Functions, Refresh

Likely the most difficult concept related to how the program displays information to the user is transactions. Before we delve into the topic, let’s review a little background information.

We developed the program to conform to the well-proven principles of Client-Server processing. One of the most basic is the practice of transmitting only the necessary information at given time (least amount). This has any benefits for the company as a whole as well as the individual users.

Client-Server Advantages:

Low bandwidth usage, allows the program to perform well in applications where the bandwidth is limited such as WAN (Wide area networking) where the user is connected to the server over a phone line (56K, ISDN, etc). Low bandwidth allows a large number of users to access the system with reasonable performance.

Client-Server Disadvantages:

Because we are only updating users on an as-needed basis, there may be times when your view of the data is no longer current.

Now, what does this mean to the average user. Generally, two users will not be working on the same customer account or the same order. But there may be times where this does happen.

For example; John starts the program and opens the Physician List. The program has displayed for John a transaction or a snapshot view of the data at the time John asked for it. For simplicity, let’s say this is Transaction stamped 9:00am today. Later Jane opens the same Physician List and gets another snapshot or Transaction stamped 9:05am.

Then at 9:10am, John adds a new physician: Jonas Salk. When he clicks the Ok button to save. He sees the new physician added to his list, because it’s his list. He sees the data as of 9:00am and the changes that he has made. This is similar to taking a picture and then later drawing on it. You can see the original picture and the changes you have made.

He then turns to Jane and asks her to call the Dr Salk and get the new address (which he did not enter). Jane searches through her Physicians, but Jonas Salk is not there. Why? Because her transaction was a snapshot of the data at 9:05am and Dr Salk was added 5 mins later at 9:10am. He does not exist in her snapshot or picture of the data.

No problem, she simply clicks the Refresh button to get a new view or snapshot of the data at 9:15am which includes Jonas Salk and continues with her project.