Chapter 3. Data Sources for Your Model
Models contain definitions of dimensions, levels, and measures. They also contain
features such as calculated measures, dimension views, or custom views that you
add to the basic PowerCube definition to meet your particular business intelligence
needs.
By querying the data in the specified sources, you create the multidimensional
PowerCubes or cube groups required by users of the IBM Cognos Business
Intelligence components, such as Analysis Studio.
Data sources can be one of the following:
v Structural (dimensional)
Contain the columns that define the model structure, such as the categories in
each dimension. Structural sources usually contain many columns and few rows.
v Transactional (fact)
Contain the columns for the measures to be tracked. They usually contain many
rows and few columns, typically one for each dimension and one for each
measure.
v Mixed
Contain the columns that define the model structure and the columns that
contain the measures to be tracked, using the same data source.
Techniques for Designing Data Sources
When setting up the data sources for your model, you should take into
consideration three principles.
These three principles are as follows:
v Where possible, design your data so that the structural information for each
dimension is provided by one source.
v Ensure that each data source contains enough information to generate the
categories for a dimension without database joins. If you must use database
joins, join queries from separate database tables using tools such as Framework
Manager, before you import the data.
v In addition to database security, be aware that different releases of Cognos
Transformer offer different options for protecting your cubes and controlling
access to information. For example, Cognos Transformer version 7.x supports
user class views whereas later versions of Cognos Transformer replace this
feature with custom views that can be associated with IBM Cognos security
objects (users, groups, and roles).
Data Source Types
Cognos Transformer supports IBM Cognos Series 7 data sources as well as
packages and reports that contain IBM Cognos query items.
This section lists the supported data sources, summarizes the information you
must specify for each data source, and identifies associated limitations.
© Copyright IBM Corp. 2007, 2011 13
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