The document discusses the architecture of Oracle Business Intelligence (OBIEE). It describes the key components including the BI Server, BI Scheduler, Repository, and data sources. It explains how queries from clients are processed, cached, and passed to underlying databases. It also covers security approaches like data level security and object level security. Repository (.rpd) files are described as containing all metadata and security rules to define OBIEE solutions. Approaches to OLAP like ROLAP, MOLAP, and hybrid OLAP are also summarized.