Pace 40 s

PO WEEKNAPPLIGATION DEVELOPMENT

JANUARY 23, 1989

In this, the
third of six col-
umns on I-CASE'
technology,
James Martin
discusses the
heart on an I-
CASE tool: the

encyclopedia, a
high-level knowl-
edge base that
stores sufficient
detail about a
procedure so
that code for the
procedure can
automatically.
Rapid advances in PC technology are
ushering in a new generation of front-
end software-development; systems
based on computer-aided systems engi-
neering (CASE) technigues. As discussed
in the first article in this series on CASE
tools, the most advanced integrated
CASE, or ICASE, tools incorporate
front-end features such as graphical de-
sign aids for the planning, analysis and
design phases of the life-cycle process,
rule-based design validation, local
knowledge coordinators and local ency-
clopedias. These PC-based, front-end
functions are tightly integrated with
mainframe-based, back-end code genera-
tors, database generators, documenta-

JAMES

MARTIN

be

EH generators and project. management

CASE tools are oriented toward the
support of systems analysts, system de-
| signers, application developers, program-
mers, engineers and system builders.

- Fully integrated CASE tools will f
mentally alter the way systems are
sordged Moe implemented and

a complete software development envi-
cle process, customization for each

AC sej workbench should implement
ronment that supports the entire life-cy-

I-CASE Encyclopedia Brings Consisteney to B

relation analysis and validation. The en-
eyclopedia stores the meanings repre-
sented in diagrams and enforces
consistency within this representation.
The encyclopedia "understands" the de-
sign, whereas a simple dictionary does
not. It is an intelligent facility, not mere-
ly a passive database.

Use of an encyclopedia: The encyclo-
pedia stores the meaning represented in
diagrams and enforces consistency with-
in this representation. Graphic represen-
tations are derived from the encyclope-
dia and are used to update it. The,ency-
elopedia contains many rules relating to
the knowledge it stores and may employ
rule-processing, an artificial-intelligence

so that code for the system can be gen-
erated automatically.

As shown in the figure below, com-
pleted design specifications from multi-
ple PC workbenches are fed to a central
knowledge coordinator and eneyclo-

a.

The knowledge coordinator ensures
consistency among the different pieces
of knowledge that reside in the ency-
elopedia. It applies Al rules to the in-
formation that is checked into the en-
eyclopedia.

The function of the central knowledge
coordinator is to provide a global analy-
sis of the design specifications from all
workbenches in order to detect inconsis-

| Code
. Generation,

Hi Central Role of Encyclopedia

v Generation
of Database

Generation of |
Documentation

RAČE a, user, powerful graphics,

 projectlevel coordination, automatic

and intelligent operation.

'Centralized repository: The heart of

a well-designed I-CASE system is an en-
PE E

David Hannum

aja eo uulates information
— relating to the planning, analjysis, construction
O vrane af nustema

teneles, arabigultjes and incom teness.
cocsstuly analyzed speciications a

the enterprise and its systems, its data
models, data flows, process models,
rules, specifications and screen designs.

Views and hyperviews: A common
term in database technology is "view."
A view of a database is a representation
of data that is perceived by one person
or program. The structure of the data-
base may be far more complex than the
structure of the view. The view shows
only those fields in which the user is in-
terested at the time.

Many views may be logically linked to
form a hyperview, just as many dia-
grams are logically linked to form a
hyperdiagram. A hyperview is a collec-
tion of knowledge about an activity or
group of activities and the data these ac-
tivities use. It can be represented with
multiple, logically related screen displays.
A hyperview is given an identification

number and is one of the formal objects
tracked by the encyclopedia.

'The central encyclopedia contains
many hyperviews. The different
hyperviews overlap; in other words,
they use common objects and employ
data derived from a common data
model.

'Consistency among diagrams: Differ-
ent types of diagrams show different
manifestations of the same information.
These diagrams are linked together into
hyperviews. Data may be entered in one
type of diagram and displayed with a
different type of diagram. The eneyclo-

pedia ensures that the different dia-
grams reflect a consistent meaning,

A person using a CASE workstation
builds his own: podal or demo is

ted in a

sistency within that hyperview. The lo-
cal hyperview is built with objects that
are extracted from a central eneyclope-
dia and use the detail that is centrally
stored. There is, thus, consistency be-
'tween the local hyperview and the cen-
tral representation.

Two implementors may create two
separate hyperviews. The central knowl-
edge coordinator has the task of exam-
ining them in combination to ensure
complete consisteney between them. In
this way, consisteney is achieved even
in a multiperson project or in a multi:
project environment.

A computer with CASE representa- ;
tions can enforce absolute consistency in.
work among many implementors.
Achieving