Today's managers must take decisions on a wide range of matters and problems - that is their position. For an
IT system, part of the data needed is stored or available as the computer database, and the rest may be stored in
the human mind as the mental database. The difference in properties and languages of these two "databases" can
produce communication problems and endanger the effectiveness of information processing. System plan, usage
and interface of the two "databases" are a critical coefficient for information decision processing. From the view
of a decision process, the purpose of building, or representing a database, is to provide data for a decision maker
in a macro perspective. But the plan of information processing means reducing the sum of information required
for a decision problem, so it is a micro perspective. This is a main difference between any database system and
the information system used for any single decision.