Monday, December 21, 2009

Cognos 8.3 -- Framework Manager -- Model objects and shortcuts

I was recently tasked with creating a relational model in Cognos Framework Manager and got a little confused when deciding what kind of objects to use. I found myself asking if I should use a Query Subject or a Shortcut. Furthermore, it seemed there had been some changes to the Shortcut functionality since I had last used Cognos. I found the following that made it rather clear which object(s) I should use when creating my model.

Taken from the Cognos documentation . . .

The main difference between model objects and shortcuts is that model objects give you the freedom to include or exclude items and to rename them. You may choose to use model objects instead of shortcuts if you need to limit the query items included or to change the names of items.

Shortcuts are less flexible from a presentation perspective than model objects, but they require much less maintenance because they are automatically updated when the target object is updated. If maintenance is a key concern and there is no need to customize the appearance of the query subject, use shortcuts.

Framework Manager has two types of shortcuts:
● regular shortcuts, which are a simple reference to the target object.

● alias shortcuts, which behave as if they were a copy of the original object with completely independent behavior.

Alias shortcuts are available only for query subjects and dimensions. Regular shortcuts are typically used as conformed dimensions with star schema groups, creating multiple references with the exact same name and appearance in multiple places. Alias shortcuts are typically used in role-playing dimensions or shared tables.

Being able to specify the behavior of shortcuts is new to Cognos 8.3. When you open a model from a previous release, the Shortcut Processing governor is set to Automatic. When Automatic is used, shortcuts work the same as in previous releases, that is, a shortcut that exists in the same folder as its target behaves as an alias, or independent instance, whereas a shortcut existing elsewhere in the model behaves as a reference to the original. To take advantage of the Treat As property, it is recommended that you verify the model and, when repairing, change the governor to Explicit. The repair operation changes all shortcuts to the correct value from the Treat As property based on the rules followed by the Automatic setting, this means that there should be no change in behavior of your model unless you choose to make one or more changes to the Treat As properties of your shortcuts.

When you create a new model, the Shortcut Processing governor is always set to Explicit. When the governor is set to Explicit, the shortcut behavior is taken from the Treat As property and you have complete control over how shortcuts behave without being concerned about where in the model they are located.

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