Information Technology Reference
In-Depth Information
\OK," said Eleanor, \I'm beginning to see how it might help, but how
do you express the interplay of responsibilities between different parts of the
business?" \Well, we need to focus on how business units interact. We can
do that by treating them as participants in a community. This involves each
participant playing a role that defines its expected behaviour and its interac-
tions with the rest of the participants. Some assignment policies could then
specify how the different participants in the organization could fulfil the roles,
and who becomes responsible for what."
\That sounds like sociology to me." \No," said Alex, smiling a little, \but
it's better to talk in these terms than to overload names that are already in
use within the organization; doing that just causes confusion."
He turned back to the whiteboard and started to sketch out a structure.
2.1
Designing with Communities
The enterprise viewpoint defines the organizational, business and social
context in which an ODP system is designed and deployed. It is primarily
through using the enterprise language that the business stakeholders and the
design team develop the shared understanding they need if the system is to
be fit for purpose. The enterprise viewpoint should be able to help answer
a set of questions about the ODP system, such as: \What is the purpose of
the ODP system?" \What are the business requirements for the system?" or
\Who are the key stakeholders and how do they interact with the system?"
Business processes are more flexible and less cleanly delineated than soft-
ware processes, so a more flexible structuring principle than traditional modu-
larity is needed. The right thing for a business system to do in some particular
circumstances is determined by a number of overlapping sets of rules, rather
than by a single algorithm; some constraints will come directly from the busi-
ness process, but others will come from organizational norms, like security
policies, or from agreements with trading partners, or even from legal con-
straints. We need to merge these various kinds of constraints. This is achieved
by basing the enterprise specification on an interrelated set of communities.
A community defines how some set of participants should behave in order
to achieve a particular objective. To make the rules reusable, they are ex-
pressed in terms of interactions between roles in the community, decoupling
their definition from the details of the resources available and the responsibil-
ities in effect at a particular instant. This is like using roles when writing the
script of a play, where the author states what each character should say, but
the actor actually playing a particular role is not determined until a particular
performance takes place. Note that, although in this chapter we just speak of
roles without always saying that they are community roles, the idea of a role
