Cloud Computing and SOA Convergence in Your Enterprise: A Step ...

104 Chapter 5 Working from Your Data to the Clouds
Logical Model
Just as with traditional database design methods, the enterprise metadata
model used for information-level architecture can be broken into two components:
the logical and the physical. And, just as with the former, the same
techniques apply to the latter. Creating the logical model is the process of
creating an architecture for all data stores that are independent of a physical
database model, development tool, or a particular DBMS (e.g., Oracle,
Sybase, Informix).
A logical model is a sound approach to an architecture project in that it
allows architects and developers the opportunity to make objective information-level
architecture decisions, moving from high-level requirements to implementation
details. The logical data model is an integrated view of business
data throughout the application domain or data pertinent to the architecture
solution under construction, typically represented as an ERD, or entity relationship
diagram (see Figure 5.8). The primary difference between using a
ACCOUNT
account type
account id
customer id (FK)
CASH MACHINE TRANSACTION
transaction id
usage date-time (FK)
transaction type
transaction sequence #
account id (FK)
customer id (FK)
account type (FK)
cash machine id (FK)
transaction amount
CUSTOMER
customer id
CASH MACHINE USAGE
cash machine id (FK)
customer id (FK)
usage date time
CUSTOMER
customer id
Figure 5.8 The logical data model is usually represented as an entity relationship
diagram. This ERD is fully attributed, meaning the entities are defined along with
the data structures. (From Linthicum, Enterprise Application Integration, Figure 6.3
p. 102, © 2000 by Addison-Wesley. Reproduced by permission of Pearson Education,
Inc.)