Database Reference
In-Depth Information
Table 10.2
Multidimensional elements in the Northwind case
study obtained using the source-driven approach
Dimensions and
cardinalities
Hierarchies and
levels
Facts Measures
Sales
UnitPrice
Product
1:n
Categories
Quantity
Product
→
Category
Discount
Supplier
1:n
Geography
Supplier
→
City
→
State
→
Region
→
Country
Customer
1:n
Geography
Supplier
→
City
→
State
→
Region
→
Country
Employee
1:n
Supervision
Subordinate
→
Supervisor
Territories
Employee
City
→
State
→
→
Region
→
Country
OrderDate
1:n
Calendar
Date
→
Month
→
Quarter
→
Semester
→
Year
DueDate
1:n
Calendar
(as above)
ShippedDate 1:n
Calendar
(as above)
Order
1:1
Document Requirements Specification
Similarly to the analysis-driven approach, all information specified in the
previous steps is documented here. This documentation includes a detailed
description of the source schemas that serve as a basis for identifying the
elements in the multidimensional schema. It may also contain elements in
the source schema for which it is not clear whether they can be used as
attributes or hierarchies in a dimension. For example, we considered that the
address of employees will not be used as a hierarchy. If the source schemas
use attributes or relation names with unclear semantics, the corresponding
elements of the multidimensional schema must be renamed, specifying clearly
the correspondences between the old and new names.
10.3.5 Analysis/Source-Driven Requirements
Specification
The analysis/source-driven approach to requirements specification combines
both of the previously described approaches, which can be used in parallel to
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