(1) The document discusses data warehousing, business intelligence, and their relationship to addressing challenges from multiple data sources.
(2) A layered scalable architecture is presented as a reference architecture for data warehouses to provide reliable, consistent, and understandable data from different source systems.
(3) Big data is also discussed in relation to data warehousing, noting differences in schema and consistency needs between traditional warehouses and big data systems handling high volumes and varieties of data.