Exploring OLAP Cube with Visual Basic - Measures and Dimensions: Cube details under investigation
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The NewOlap database in the Analysis Server Nechost has a Cube, MyFirstCube. This is created from an OLTP database, the Northwind example database that is available in an out of the box installation of MS SQL Server 2000, and MS Access database products. This is shown in the next figure.
The various tables used in constructing NewOlap are shown in the Schema. The Schema of a cube is the various tables used in configuring the cube. This Schema is different from the OLTP schema.
There are two types of schemas common in OLAP data. One is called the Star schema, wherein the measures table relates directly to each of the existing dimension tables. The other type, called the Snowflake schema, which may include tables not directly accessible by the measures tables, but through another dimension. The MyFirstCube used in the previous tutorial must have been correctly labeled, snowflake, rather than star. The next figure shows the Schema of MyFirstCube in the Analysis Server's Editor window.
As data is added to the database, the cube data needs to be refreshed. Thus, it is necessary to process the data. The control that is used to process can be accessed by right clicking the Cube and clicking on the Process.. menu item from the pop-up contextual menu. For this to work correctly the backend SQL Server containing the OLTP data must be running. When the process is run successfully, the following process monitoring window shows up. Depending upon the amount of data to be processed, and the hardware resources available, it may take a certain amount of time.
Next: Using VB to Explore the OLAP Cube: Creating a VB Project >>
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