We can divide IT systems into transactional (OLTP) and analytical (OLAP). In general we can assume that OLTP systems provide source data to data warehouses, whereas OLAP systems help to analyze it.
OLAP (online analytical processing): is computer processing that enables a user to easily and selectively extract and view data from different points of view.
For example, a user can request that data be analyzed to display a spreadsheet showing all of a company’s beach ball products sold in Florida in the month of July, compare revenue figures with those for the same products in September, and then see a comparison of other product sales in Florida in the same time period.
OLTP ( Online transaction processing) : is a class of information systems that facilitate and manage transaction-oriented applications, typically for data entry and retrieval transaction processing.