OLAP and OLTP can be easily confused. A quick summary of the differences

OLTP: Online Transaction Processing; enables real-time execution of large numbers of database transactions typically updating data in multiple tables with foreign keys and providing transactional guarantees and rollbacks.

OLAP: Online Analytical Processing; system to enable multi-dimensional analysis of large volumes of data typically for reporting purposes. Backing data is typically some sort of data warehouse but can also be an OLTP data store.