This paper provides an overview of data warehousing and on-line analytical processing (OLAP) technologies, emphasizing their unique requirements compared to traditional online transaction processing (OLTP). Data warehousing is a collection of decision support technologies aimed at enabling better and faster decision-making by knowledge workers. The paper discusses the architecture and end-to-end process of data warehousing, including data extraction, cleaning, transformation, loading, and refreshing. It highlights the importance of multidimensional data models and the use of front-end tools for querying and data analysis. The paper also covers server extensions for efficient query processing, metadata management, and warehouse management tools. Additionally, it identifies research issues in data warehousing, such as data cleaning, physical design, and resource management, and suggests areas for further research. The authors draw from their experience at the VLDB Conference in 1996 and provide a comprehensive roadmap for understanding and implementing data warehousing and OLAP technologies.This paper provides an overview of data warehousing and on-line analytical processing (OLAP) technologies, emphasizing their unique requirements compared to traditional online transaction processing (OLTP). Data warehousing is a collection of decision support technologies aimed at enabling better and faster decision-making by knowledge workers. The paper discusses the architecture and end-to-end process of data warehousing, including data extraction, cleaning, transformation, loading, and refreshing. It highlights the importance of multidimensional data models and the use of front-end tools for querying and data analysis. The paper also covers server extensions for efficient query processing, metadata management, and warehouse management tools. Additionally, it identifies research issues in data warehousing, such as data cleaning, physical design, and resource management, and suggests areas for further research. The authors draw from their experience at the VLDB Conference in 1996 and provide a comprehensive roadmap for understanding and implementing data warehousing and OLAP technologies.