Datawarehouse Concepts

1. Different Storage modes in OLAP

 . ROLAP / MOLAP / HOLAP

 . Adv & Dis-Adv of each storage mode

. http://www.sql-server-performance.com/2013/ssas-storage-modes/

. http://msdn.microsoft.com/en-us/library/ms174915.aspx

. http://stackoverflow.com/questions/17774236/sql-server-rolap-vs-molap-vs-holap

* Imp

 . what is the difference between Tabular Modelling & ROLAP


2. Types of schemas in Datawarehousing

. Star

. Snowflake

. Galaxy

3. Types of dimensions and facts in Datawarehouse

 . Adv & Dis-Adv, how to avoid the Dis-Adv

3a. Degenerate Dimension / Fact Dimension

. http://www.kimballgroup.com/2003/06/03/design-tip-46-another-look-at-degenerate-dimensions/

. http://www.datamartist.com/degenerate-dimensions-in-datamarts

. http://www.information-management.com/news/7844-1.html

* Imp
. How is a degenerate dimension loaded in SSAS
. http://msdn.microsoft.com/en-us/library/ms175669%28v=sql.90%29.aspx

3b. Junk Dimension

. http://www.datamartist.com/mystery-or-junk-data-warehouse-dimensions

. http://en.wikipedia.org/wiki/Dimension_(data_warehouse)

3c. Role Playing Dimension

. http://www.sqlservercentral.com/blogs/jamesserra/2011/11/28/role_2D00_playing-dimensions/

3d. Conformed Dimension

. http://en.wikipedia.org/wiki/Dimension_(data_warehouse)

3e. Slowly Changing Dimension

. Type 0/1/2/3

3f. Late arriving Dimension

3g. Causal Dimension

3h. Factless Fact