What Does Multidimensional Online Analytical Processing Mean?
Multidimensional online analytical processing (MOLAP) is a kind of online analytical processing (OLAP) that, like relational online analytical processing (ROLAP), uses a multidimensional data model to analyze data. The difference between MOLAP and ROLAP is that MOLAP requires that information first be processed before it is indexed directly into a multidimensional database, whereas ROLAP is entered directly into a relational database.
Techopedia Explains Multidimensional Online Analytical Processing
Most end users prefer MOLAP because of its better speed and user-responsiveness. In general, OLAPs uses multidimensional data models. As a result, users are able to view different features and aspects of the data. While ROLAPs use relational databases, this limits the viewing of data by consecutively accessing and processing a table for each feature or aspect of the total data. In that case, an advantage of MOLAP is its ability to process and store the data in a multidimensional array. All the possible arrangements and combinations of data are shown in the array and can be accessed directly.
The key advantages of MOLAP include:
- Excellent performance. MOLAP cubes are built for fast data retrieval and are therefore the best for “slicing and dicing” operations.
- The ability to quickly perform complex calculations because they have been pre-generated during creation of the cubes.
Although MOLAP appears to be better than other kinds of OLAPs, it still has some downsides. Because MOLAP processes the data first, the processing time in some solutions could be quite lengthy, particularly when large volumes of data are involved. It also appears to have difficulty in querying models with high cardinality dimensions.