Databases Reference
In-Depth Information
Architecture (SOA) were carried out taking into account
legacy databases without restructuring them. Companies did
not have the means nor the objective to modify these
databases. The IT industry
1
has largely maintained the idea
that new technologies would be capable of offering a return
on investment without modifying the core of existing
systems. Now, companies are realizing that these new
technologies have been oversold. It is now obvious but it was
not easy to convince people that, if data is no longer reliable,
then the software that use them are also no longer reliable,
whether they be oriented objects, BPM, SOA or others.
During the past few years, there has been a steady decline
in the quality of data and data modeling expertise is
becoming increasingly rare. It is more common to hire a Java
engineer than a UML data modeler. It is even present in
computer science training courses, surely a sign that this
decline runs deep. And yet, in the first days of IT, a formal
approach to data existed. Procedures and methodology were
set in stone with
2
:
-
conceptual data modeling to present business
information in a format that can be understood by people
who are not technical specialists;
-
logical data modeling for the translation of conceptual
modeling to data structures that respect IT needs and
feasibility;
-
physical data modeling for the translation of logical
modeling into software, i.e. the “physical database schema”.
1. Software vendors, consulting groups, IT services companies, etc.
2. This terminology was incarnated in the MERISE methodology in
France, from the 1970s. The same levels appear in several English
language approaches that have been around for some time, in particular
the Zachman Framework
from about the middle of the 1980s.
