Concepts:
On-line processes which acts as an interface between
the
user and the database presents
only User data-iems.
Identification of tables and field name simply from the user
interface screen fields means
expecting one-to-one
relationship between User data-item and System data-item(Table
and field). It will not be the case always.
The difference between data-items users interact with
and
fields of the table
is due to Normalization,
Parameterization and other reasons[Ref. 1.2].
This mismatch between UDI and table-field
makes the
production of organizational documents, reports and
forms
more involved. The complexity of report is due to the lack
of one-to-one correspondence between the user
data-items
and system data-items.
Ref. 1.2
-----------------------
Reasons for the lack of one-to-one relationship
between
Organizational User data-items and Physical database are :
1. Implementation of RDBMS requires Normalization of data-
items. Normalization breaks the user data-items into atomic
data-items, establishes the one-to-one relationship
and
removes transitive relationship among these data-items.
Result of all this is that the database of the Organization
is much different from the user data-item
set of the
Organization.
2. This difference between the database and the user data-
item list increases further due to Parametrization of
the
Information Management System.
Parameters introduce
flexibility in the system making it easier to infuse the on-
going changes of the Enterprise decision system into
the
Information system. Parameters increase the distance between
the entity-user data-item relationship of the organization
and relationship among tables in the database.
3. Sometimes an organization is so big that it has different
types of information which are similar in structure and may
be kept in the same table. These
different types of
Information is qualified so that it is possible to point to
one kind of Information Use of this
type of database
increases the difference between the database and the Entity-
User data-item list even further.
4. There are many more decisions that are taken during
the
database design. All these increases the difference between
Data-items kept in the
database and Data-items
required(used) by the Organization.