Database Reference
In-Depth Information
Date
Dimension
Date key
Date day
Date mo
Customer
Dimension
Customer key
Customer ID
Product
Dimension
Product key
Product name
Product price
Fact Table
Date key
Customer key
Product key
Sales key
# occurrences
Sales
Dimension
Sales key
Sales person
Sales code
FIGURE 6.4
A dimensional model.
HOLAP : Hybrid On-Line Analytical Processing (HOLAP) tools use
the best features of multidimensional and relational databases.
Relational databases are best known for their flexibility. Until
recently, relational databases were weak in their ability to perform
the same kind of multidimensional analysis that the multidimen-
sional databases are specifically optimized for. The introduction of
hybrid relational systems with enhanced abilities to manipulate star
schemas has increased the OLAP capabilities to the relational world.
Hybrid tools provide high performance for both general-purpose
end users and power users.
WOLAP : Web-enabled OLAP.
CUBE : In a multidimensional database, a dimensional model is a cube.
It holds data more like a 3-D spreadsheet rather than a traditional
relational database. A cube allows different views of the data to be
quickly displayed. The ability to quickly switch between one slice of
data and another allows users to analyze their information in smaller
meaningful chunks, at the speed of thought. Use of cubes allows the
user to look at data in several dimensions, e.g., attendance by depart-
ment, attendance by attendance codes, attendance by date, etc.
 
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