Flattening a data set into an event log can be compared to aggregating multidimensional data in Online Analytical Processing (OLAP). For example, using a typical OLAP tool, sales data can be viewed by product categories, by region, and/or by quarter. Depending on the type of question, a different view on the data can be chosen. One important difference is that in process mining we analyze processes rather than a simple OLAP cube. Therefore, we need to correlate events and order them, thus making the extraction process more complex.