In order to retrieve data from a source you need information about the source such as the name of the source, the method used to retrieve the data, security permissions needed to retrieve the data, and so on. All this information is encapsulated into an object called a Data Source in SSAS 2008. An Analysis Services database contains a collection of Data Sources, which stores all the data sources used to build dimensions and cubes within that database. Analysis Services will be able to retrieve source data from data sources via the native OLE DB interface or the managed .NET provider interface.
In the simplest case you will have one data source that contains one fact table with some number of dimensions linked to it by joins; that data source is populated by data from an OLTP database and is called an Operational Data Store (ODS). Figure 4-1 shows a graphical representation of this data source usage. The ODS is a single entity storing data from various sources so that it can serve as a single source of data for your data warehouse.
A variant on the data source usage, which is enabled by the UDM first introduced in Analysis Services 2005, is the ability to take data directly from the OLTP system as input to the BI application. This is shown in Figure 4-2.
Prior to the introduction of the Analysis Services UDM, certain ...