OLAP – OnLine Analytical Processing ROLAP – Relational OnLine Analytical Processing MOLAP – Multidimensional OnLine Analytical Processing HOLAP – Hybrid OnLine Analytical Processing DOLAP – Desktop/Database OnLine Analytical Processing WOLAP – Web Enabled OnLine Analytical Processing Read more here – https://social.technet.microsoft.com/wiki/contents/articles/19898.differences-between-olap-rolap-molap-and-holap.aspx