Data Warehouses and Decision Support Systems

This lecture covers the concepts of data warehouses, decision support systems, and online analytical processing (OLAP). It explains the importance of integrating data from various sources, handling complex ad-hoc queries, and the challenges of semantic integration and heterogeneous data sources. The instructor discusses the structure of data lakes, the formats of data stored in them, and the issues related to querying huge datasets. Additionally, the lecture delves into multidimensional data models, star and snowflake schemas, OLAP queries, and the use of the CUBE operator for computing super-aggregates. Various optimizations such as bitmap indexes, join indexes, and star joins are also explored.