Difference between a data source and data source view

Q 3 : What is the difference between a data source and data source view ?

A Data Source represents a connection to a particular data source using one of the supplied providers. A Data Source View is an abstraction layer that you design using a data source. The latter also contains expressions that create calculated fields.

Difference between online and offline mode in SSAS

Q 2. What is the difference between online and offline mode in SSAS ?

Online mode means that you are directly connected to a particular SSAS database instance. Any changes you make are implemented on save. Offline mode means that means that you are creating metadata files that can be deployed to the SSAS server when you want. An important consideration for offline mode is that BIDS includes no granular conflict resolution.

Aggregation types are available for measures in BIDS

Q 4 : What aggregation types are available for measures in BIDS ?

The default aggregation is SUM. Other available aggregation types include the following: MIN, MAX, COUNT, DISTINCT COUNT, AVERAGE OF CHILDREN, FIRST CHILD, LAST CHILD, FIRST NON EMPTY, LAST NON EMPTY. You can also design custom aggregations using MDX.

What is star schema

Q 1. What is star schema in SSAS ?

A star schema is a type of modeling used as a basis for  building an OLAP cube. It consists of at least one fact table and many dimension tables. The rows in the dimension tables have a 1:M relationship with the rows in the fact table.

In a star schema every dimension table is related directly to the fact table.