1219
Chapter 53: Building Multidimensional Cubes in Analysis Services with MDX
53
Data Storage
The data storage strategy chosen for a cube and its components determines not only how to
store the cube , but also how to process it. You can set storage settings at three different
levels, with parent settings determining defaults for the children:■ (^) Cube: Begin by establishing storage settings at the cube level (sets defaults for
dimensions, measure groups, and partitions). Access the Cube Storage Settings dia-
log by choosing a cube in the Cube Designer, and then clicking the ellipsis on the
Proactive Caching property of the cube.
■ (^) Measure Group: Use when storage settings for a particular measure group differ
from cube defaults. Access the Measure Group Storage Settings dialog by either
clicking the ellipsis on the measure group’s Proactive Caching property in the Cube
Designer or by choosing the Storage Settings link in partition view without high-
lighting a specifi c partition.
■ (^) Object level (specifi c partition or dimension): Sets the storage options for a sin-
gle object. Access the Dimension Storage Settings dialog by clicking the ellipsis on
the dimension’s Proactive Caching property in the Dimension Designer. Access the
Partition Storage Settings dialog by selecting a partition in the partition view and
clicking the Storage Settings link.
Each of the storage settings dialogs are essentially the same, differing only in the scope of
the setting’s effect. The main page of the dialog contains a slider that selects preconfi gured
option settings — from the most real-time (far left) to the least real-time (far right).
By default, the pure MOLAP setting is chosen and works well for traditional data warehouse
applications. However, if you build a partition based on frequently changing source data
(for example, directly on OLTP tables), then proactive caching can automatically manage
partition updates.
Cube Processing
Before browsing or querying the cube, you must refresh the data it contains by processing
the cube. You generally accomplished this on a regular schedule through SQL Server Agent
or an SSIS package after you update the data warehouse.Processing Methods
You can process the cube as a whole or individual object such as the dimensions or a single
partition. This is particularly useful so that you can process different partitions on differ-
ent schedules. Several options are available when you process the cube and vary it basedc53.indd 1219c53.indd 1219 7/31/2012 10:30:26 AM7/31/2012 10:30:26 AM
http://www.it-ebooks.info