Chapter 2. Proven Practice

This chapter covers ideas for best practices in creating your Framework Manager model.

The topics covered in this chapter include:

• Using namespaces to divide the model into layers

• Using folders within namespaces to provide logical grouping of data

• Renaming columns within tables, and use of shortcuts to allow the report designer to know where the data originates from

• Using Model Advisor to diagnose potential design problems

By the end of this chapter, you will have an understanding of the proven practices to use while designing a new data model in the Framework Manager.

Framework Manager is the modeling design tool used to model the metadata of your database to allow report authors to produce reports using the available reporting studios on the IBM Cognos BI reporting server.

Modeling layers

One of the basic principles of a good model design is to divide the model into a series of layers, each layer having a specific function within the model and a related set of modeling activities.

Originally IBM Cognos recommended the use of two layers, a data layer and a modeling layer. This was later refined by the inclusion of a Presentation layer, and a separate Dimensional layer if the Dimensional Modeled Relational (DMR) data is also used in the model.

The layers are built upon one another, with the lowest level being the data layer, the modeling layer as the middle layer, and the top layer being the presentation layer. The dimensional layer can be used to replace the presentation layer, or can be used in addition to the presentation layer.

Data layer

The data layer, also called the import layer, or the physical layer, contains the data source query subjects. This is directly based on the underlying database objects.

In order to retrieve the table information, you should...

How to create namespaces

In the Framework Manager, a namespace is a method for grouping objects based on their functionality, for example, for creating the layers of our model. When you create a namespace and publish your package, the items used by the report authors will be prefixed by the name of the namespace. You can have namespaces within namespaces, and each namespace name will have prefix items within the namespace.

The following are the steps to create a namespace:

1. Select the location where the namespace is to be created.

2. Right-click on the Options menu and select Create | Namespace:

   

   Alternatively, from the menu select Create | Namespace.

3. Give your namespace a name to replace the default name, Namespace. All the names within the model must be unique.

After creating your namespace, you may drag-and-drop the objects into it.

How to create folders

When you publish your package containing folders, the folders are visible to the report authors but unlike namespaces, they are not prefixed to the reporting items.

Unlike namespaces, the folder names are also not prefixed to the items within the folder.

The folders are also created in a similar way to the namespaces:

1. Select the location where the folder is to be created.

2. Right-click on the Options menu and select Create | Folder.

   Alternatively, from the menu select Create | Folder.

3. Give your folder a name to replace the default name. All folder names must be unique within a namespace.

4. You can select and move the objects into the folder, or alternatively click on the Finish button to confirm the folder creation.

After creating your folder, you can drag-and-drop other objects into it.

Using the Model Advisor

While creating your framework model, the Model Advisor can be used to verify whether your model follows the current best practice in modeling and also helps to identify those areas of the model that you need to examine and change.

The Model Advisor is not a replacement for an experienced modeler and it should be seen only as a diagnostic tool to assist and improve the model design.

You can run the Model Advisor against the whole model or a subset of the model, and you may also choose which tests should be run against your model.

Tip

Before using the Model Advisor you should verify the model and fix any errors.

If you are analyzing a newly created model, consider the following points:

• Analyze any newly imported objects, especially their relationships and determinants

• As you import additional database objects and add new relationships and determinants to your model, use the Model Advisor to analyze each change for potential issues

• Before you publish your model for the first...

Summary

In this chapter, we have looked at some proven practice techniques for improving your modeling with Framework Manager, namely the use of layers to divide your model into functional levels.

We have also looked at the Model Advisor tool, which can be used to diagnose problems with your model, so that if necessary they can be corrected before your model is published.

In the next chapter, we will look at how to import the relational metadata into your new Framework Manager project.