What is the difference between a data warehouse and a data mart?

• A. Data warehouses are large collections of data from several different sources and data marts are smaller collections that could be from a single department
• B. Data warehouses are large collections of data from one source which are then sent out to data marts
• C. Data warehouses are large collections of data from several different sources and data marts are smaller collections that could be from a single department
• D. Data warehouses are large collections of data from several different sources and data marts are where the data is purchased

Answer: (C)

Understanding the difference between a data warehouse and a data mart comes down to scope and purpose. A data warehouse is the organization’s centralized, integrated repository that pulls data from many different sources across the enterprise, designed to support broad reporting and analytics with consistent definitions and governance. A data mart, on the other hand, is a smaller, focused subset of data that serves a single department or business function, providing fast access to the information that specific teams need. It can be built from the warehouse or directly from source systems to meet department-specific analytical needs.

Therefore, the best description is that the warehouse aggregates data from several sources, while the data mart comprises smaller, department-focused data tailored for specific users. Data marts are not about purchasing data; they are targeted stores to support particular business units.