Dimensional modeling (DM) names a set of techniques and concepts used in data warehouse design. It is considered to be different from entity-relationship modeling (ER) and doesn’t necessarily involve a relational database. Dimensional modeling is a design technique for databases intended to support end-user queries in a data warehouse. It is oriented around understandability and performance.
A multidimensional database (MDB) is a type of database that is optimized for data warehouse and online analytical processing applications. Multidimensional database technology is a key factor in the interactive analysis of large amounts of data for decision-making purposes. Multi-dimensional databases are specially useful in sales and marketing applications that involve time series. Large volumes of sales and inventory data can be stored to ultimately be used for logistics and executive planning.
The most commonly used schema design in OLAP applications is STAR SCHEMA.
Star Schema is a relational database schema for representing multidimensional data. It is the simplest form of data warehouse schema that contains one or more dimensions and fact tables. It is called a star schema because the entity-relationship diagram between dimensions and fact tables resembles a star where one fact table is connected to multiple dimensions. The center of the star schema consists of a large fact table and it points towards the dimension tables. The advantage of star schema are slicing down, performance increase and easy understanding of data.