Chapter 2. IBM Cognos Dynamic Cubes architecture 13
Figure 2-4 shows routing of a query to a summary table.
Figure 2-4 Routing of a query to a summary table
2.1.2 Modeling dynamic cubes
Cognos Cube Designer is used to model dynamic cubes on star or snowflake data
warehouses that are stored in a relational database. Cognos Cube Designer analyzes a cube
model as it is being constructed to ensure the underlying data warehouse is truly a star or
snowflake, and raises exceptions if it recognizes relationships in the data that contradict
constraints of either data topology.
A Cognos Cube Designer project can contain one or more namespaces. A namespace can
contain a collection of dimension definitions which can then be used to model one or more
cubes within the namespace. A dynamic cube is associated with a single fact table in the
underlying data warehouse and contains dimensions defined either in the encompassing
namespace, or within the cube itself, that is, dimensions which are specific to a particular
cube.
Time
Ye a r
Quarter
Month
Sto r e s
Country
St a t e
City
St o r e
Measur es
Cost
Year Quarter Coun try Stat e Cit y Cos t
Year Quarter Month Country Cost
Year Country State Cost
Summary1
Summary2
Summary3
Dimensions
Month Store Cost
Fact Table
Data Re qu e ste d Wit ho ut Su mmaries Wit h Summa ries
Co s t by Ye ar , St at e SUM( Fa ct.Cost)
GRO UP BY Year, S tore
SUM( Su mmary3 .Cost)
GROUP BY Ye ar , S tore
Cost by Quarte r, C ountry SUM( Fa ct.Cost)
GRO UP BY Quarter , Coun try
SUM( Su mmary2 .Cost)
GROUP BY Quart er, Coun try
Co s t by Qu ar te r , St at e SUM( Fa ct. Co s t)
GRO UP BY Quarter , S ta te
SUM( Su mmary1 .Cost)
GROUP BY Quarter, S ta te