Data Entry, Update and Viewing
Database
Data Access Method
Report Writer

Data Entry, Update and Viewing
Database
Data Access Method
Transaction Log
Data Extraction
Local Data
Report Writer

The major interaction users have with computer information systems should be through the use of computer application screens. These screens can be used for entering, updating and correcting information. Also screens can be designed to provide the latest information upon request. The application should be easy to use allowing people to maintain their own information while making it available to all who need it. The screens should use techniques and building blocks that are commonly used in popular computer applications. These building blocks of a screen are called controls. They include text boxes, check boxes and date entry controls. Examples of these are described in the Screen Blocks page.
 

Most modern computer information systems use a database to store the information. This can be a simple file system like dBase or an application database like Microsoft Access. Larger systems will use database servers like Advantage, SQL Server and Oracle. Many times an application will start out small used by only a few people and then grow to many users. So, the ability to scale an application from small to large can be important. The major factor that influences the utility and productivity of a computer information system is the ability of the users to understand and interact with the information. Therefore, the database design should be translatable into a simple set of tables to which users can relate.
 

In multi-user systems data access must be controlled to prevent corruption or loss. Two popular methods could be called Library Check Out and Transaction Processing.
The Library Check Out method or some variation of it is used in many applications. This is a method like checking out a book from the library. Only one person can have the book at a time. This can work well in a small network of local computers where users rarely work with the same item of information. But, sometimes in large geographically disperse systems information can be lost. This can lead to mistrust of the system and lost user time checking to make sure information is correct.
The Transaction Processing method is like making a reservation through a modern computer system. A person makes a request and the the reservation is made or rejected. In the example above, the system indicates a wait state while the system attempts to make the update. If the update is rejected a message shows the reason.
 

The transaction log shown here is from a Transaction Processing system that records the time, date, who and computer used for the transaction. It also records the before and after values for each field that changed. While some of this information might be useful for tracking the use of the computer information system. The major utility of this log is to provide a simple source for synchronizing the information in a backup or portable system.
 

Report writers and report programs must select information from the database to start the reporting process. This requires moving the data to a working directory on the local machine. While many report writers do this as part of the report generation process, the extraction process can be performed more efficiently by a program that understands the data environment. Also one extraction can be used to generate multiple reports. The data for all reports is the same regardless of on going updates. This also prevents multiple users from interfering with each other since the extraction resides on their own local computer. Using one simple interface that can be used with many different databases limits the education needed, making the information more available to the user.
 

When data is extracted from a database system it is stored on the local computer. This makes it easily accessible for multiple reports as needed. Reports that involve complex interaction where the information is processed repeatedly can be done efficiently because all of the data is on the local computer.