Data warehouse
A large store of data gathered from a wide range of sources, both old and new, within a company (and sometimes externally) and used to guide business decisions. Data is processed and cleaned to ensure there are no errors before it goes into the store. A company will have many databases which are unlinked, a data warehouse brings them together to help generate new information.
Data marts
A data mart is a subset of the data warehouse and is provided to a specific business department or team.
Data mining
The practice of examining a data mart (a subset of the data warehouse) in order to generate new information.
Data privacy laws are still be to considered (as well as ethics) for data warehouses.