OLAP Server Architectures
Relational OLAP (ROLAP)
- Use relational or extended-relational DBMS to store and manage warehouse data and OLAP middle ware to support missing pieces
- Include optimization of DBMS backend, implementation of aggregation navigation logic, and additional tools and services
- greater scalability
Multidimensional OLAP (MOLAP)
- Array-based multidimensional storage engine (sparse matrix techniques)
- fast indexing to pre-computed summarized data
Hybrid OLAP (HOLAP)
- User flexibility, e.g., low level: relational, high-level: array
Specialized SQL servers
- specialized support for SQL queries over star/snowflake schemas