What Is OLAP?
OLAP is software for performing multidimensional analysis at high speeds on large volumes of data from a data warehouse. Most business data have multiple dimensions—multiple categories into which the data are broken down for presentation, tracking, or analysis. For example, sales figures might have several dimensions related to location, time, product, and more. But in a data warehouse, data sets are stored in tables, each of which can organize data into just two of these dimensions at a time. OLAP extracts data from multiple relational data sets and reorganizes it into a multidimensional format that enables very fast processing and very insightful analysis.
Why OLAP
The core of most OLAP systems, the OLAP cube is an array-based multidimensional database that makes it possible to process and analyze multiple data dimensions much more quickly and efficiently than a traditional relational database. A relational database table is structured like a spreadsheet, storing individual records in a two-dimensional, row-by-column format. SQL and relational database reporting tools can certainly query, report on, and analyze multidimensional data stored in tables, but performance slows down as the data volumes increase. This is where the OLAP cube comes in.
What Is an OLAP Cube?
The OLAP cube extends the single table with additional layers, each adding additional dimensions.
| For example, the top layer of the cube might organize sales by region; additional layers could be country, state/province, city and even specific store. In theory, a cube can contain an infinite number of layers (called a hypercube.) |
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| He who fails to plan is planning to fail. |