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system using business terminology and the data warehouse team develops
the system using a more technical viewpoint that is dicult for the users to
understand.
Advantages of the analysis-driven approach are
￿ It provides a comprehensive and precise specification of the needs of
stakeholders from their business viewpoint.
￿ It facilitates, through the effective participation of users, a better under-
standing of the facts, dimensions, and the relationships between them.
￿ It promotes the acceptance of the system if there is continuous interaction
with potential users and decision makers.
￿ It enables the specification of long-term strategic goals.
However, some disadvantages of this approach can play an important role
in determining its usability for a specific data warehouse project:
￿ The specification of business goals can be a dicult process, and its result
depends on the techniques applied and the skills of the developer team.
￿ Requirements specification not aligned with business goals may produce
a complex schema that does not support the decision processes at all
organizational levels.
￿ The duration of the project tends to be longer than the duration of the
source-driven approach. Thus, the cost of the project can also be higher.
￿ The users' requirements might not be satisfied by the information existing
in the source systems.
10.7.2 Source-Driven Approach
In this approach, the participation of the users is not explicitly required.
They are involved only sporadically, either to confirm the correctness of
the structures derived or to identify facts and measures as a starting
point for creating multidimensional schemas. Typically, users come from
the professional or the administrative organizational level since data are
represented at a low level of detail. Also, this approach requires highly skilled
and experienced designers. Besides the usual modeling abilities, they should
have enough business knowledge to understand the business context and its
needs. They should also have the capacity to understand the structure of the
underlying operational databases.
The source-driven method has several advantages:
￿ It ensures that the data warehouse reflects the underlying relationships in
the data.
￿ It ensures that the data warehouse contains all necessary data from the
beginning.
￿ It simplifies the ETL processes since data warehouses are developed on
the basis of existing operational databases.
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