Providing Access to External Databases - High-Performance Web Databases: Design, Development, and Deployment - page 486

offer significant economic advantages over others. Many employees are
unaware of this and select an information provider without researching
sources. In addition, there may be significant differences in the manner in
which the providers offer access to external database information. This
fact can profoundly affect the ability of organizational personnel to work
with the information they require.
When developing a list of external databases, the database manager will
probably receive employee requests in the form of trademark or service-
mark names. Those names may not represent the actual type of informa-
tion organizational employees need to access, nor do they necessarily
reveal whether equivalent information can be obtained from another infor-
mation access provider. Thus, the trademark or servicemark name should
be converted into a descriptive statement of the employee's information
access requirement.
For example, an employee may request access to Dow Jones Information
Services, but after questioning the employee, the database manager might
determine that he or she actually needs to access a very limited amount of
financial information, such as the relationship between German marks and
US dollars over the past five years. This should be the database manager's
external database access requirement. Specifically saying what is needed
helps the manager locate alternative information access providers and
avoid paying for unnecessary information.
After defining the necessary content of external databases, the database
manager should try to locate alternative information providers. In doing
so, the manager should note the method or methods by which information
can be accessed. This is the third step in developing an effective strategy
for accessing external database information.
INFORMATION ACCESS METHODS
Data communications is just one of several methods for accessing exter-
nal databases that the database manager should consider. Other methods
include optical and magnetic media distributed as part of a subscription
service, as well as conventional printed media. Even when considering the
use of data communications, the database manager should look at several
access methods.
Some information access providers can be reached only through a
direct-dial modem call. Such providers may not have a national toll-free
number, and the database manager must include the cost of long-distance
telephone communications, as well as the cost of accessing information,
when evaluating these providers. Other providers that support modem
access may be connected to such value-added carrier X.25 based packet
transmission networks as SprintNet or BT Tymnet. Using those networks to