In SSAS, there are two ways to design dimensional models. Top-down or bottom up.
Top Down Approach
- This is generally not much used option.
- The relational data source does not exist in this case. The tables are created from the dimensional model from SSAS.
- Cube and dimension wizards has the option to implement this option.
- Schema Generation Wizard is used to generate and deploy schema in the database..
- DBO permission required in order to create database objects.
Bottom Up Approach
- Most of the times this is the approach thats taken.
- The data mart already exists.
- The dimensional model and cubes are designed from the Relational tables in the Data Mart.
- Cube and Dimension wizards have the option to implement this solution.