OLAP Implementation The earliest OLAP systems used multidimensional arrays in memory to store data cubes,and are referred to as multidimensional OLAP (MOLAP)systems. OLAP implementations using only relational database features are called relational OLAP(ROLAP)systems Hybrid systems,which store some summaries in memory and store the base data and other summaries in a relational database,are called hybrid OLAP(HOLAP)systems. Database System Concepts-5th Edition,Aug 26,2005 18.12 @Silberschatz,Korth and SudarshanDatabase System Concepts - 5 18.12 ©Silberschatz, Korth and Sudarshan th Edition, Aug 26, 2005 OLAP Implementation The earliest OLAP systems used multidimensional arrays in memory to store data cubes, and are referred to as multidimensional OLAP (MOLAP) systems. OLAP implementations using only relational database features are called relational OLAP (ROLAP) systems Hybrid systems, which store some summaries in memory and store the base data and other summaries in a relational database, are called hybrid OLAP (HOLAP) systems