Databases Reference
In-Depth Information
Exhibit 25-1. Two-tier application architecture.
information is represented in T3, then all applications involving T3 (in this
case Applications A1, A2, and A3) have to be updated. In addition to requir-
ing duplication of effort this design increases the risk of application mal-
function, since it is possible to miss updating an application which needs
updating. Also note that even aside from complicating change management,
this design involves duplication of effort in terms of data access as well as
relational to object mapping.
In order to solve the above-mentioned problems, modify the design to
produce a more object-oriented approach by introducing components.
Exhibit 3 introduces a component C1 that encapsulates sub data model M1.
This makes C1 a data-component. Consequently, to the methodology illus-
trated in Exhibit 3 is referred to as the data-component approach.
ADVANTAGES/FEATURES OF THE DATA-COMPONENT APPROACH
The data-component approach, as illustrated in Exhibit 3, offers the fol-
lowing features and advantages:
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