Personal computers have allowed data architecture to include options such as client/server and personal databases. It has also opened up a market for database companies to design systems that target the desktop environment.
There is a danger of repetition and redundancy, the same application may be developed and the same data may be stored in many different systems. The data on the systems are also not readily shareable. The data may not be as reliable and may not be updated as often as desirable. The databases are not always secure nor are they always backed up. When the user is no longer in charge of the database, the application and data are often lost because they are not documented or the organization does not realize they exist. Finally, some individuals may spend more time fiddling with the database and not getting their assigned work done.
File/server systems have two problems:
Client/server is likely to be a cheaper information procession solution than host/terminal when processing can be shifted from mainframe to clients. When the mainframe is primarily a data store and does little processing, little is gained by shifting processing to a client. Also, if there are a few common transactions performed by the users, there is little to be saved from reduced training.
Client/server may also reduce the cost of computing by allowing a company to get out of a monopolistic situation with mainframe hardware and software to a more open system provided by client/server. Frequently client/server technology is also easier to use and thus operational costs of applications may be lower in a client/server environment. Improved ease of use may also translate into higher software quality, easier application maintenance, and applications with fewer bugs that cost less to maintain.
When a firm moves from a centralized database to a distributed database it may lower its communication costs. This happens because the data that are most frequently accessed by a specific location are located at that location; thus there are lower communication costs to retrieve it. A distributed database is more complex than a centralized one and may be more costly to develop and maintain.
Transparency in the context of a hybrid architecture is that the user sees the database system as a seamless system that readily provides needed information. The location of the data, the storage format, and the access method should be invisible to the user.
DBMS independence refers to the ability to set an organizational standard for DBMSs and allow the local sites to utilize whatever DBMS they want as long as it confirms to the organizational standard. For instance, the standard may be a relational database that uses standard SQL in which case several different DBMSs can be used that fit this requirement.
Remote job entry allows the professor to manage her data locally while executing the complex model remotely.
Client/server: The personal bankers will need an easy to use system in order to perform a wide range of transactions. The bankers will also need to share a significant amount of information.
For the company to effectively create a global database they will probably need to design a distributed database utilizing client/server technology. Because each country has its own database, it is probable that the database can be fragmented in such a way that the data most often used by each country will reside within that country. The key factors include knowing how the data are used, what kind of database is currently in place, and the independence of the separate databases in terms of the hardware, operating system, network, and DBMS. Problems to anticipate include:
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This page is part of the promotional and support material for Data Management (fifth edition) by Richard T. Watson |