FUNDAMENTALS OF COMPUTER

Detailed explanation-1: -6. Answer-D) Small logical units where data warehouses hold large amounts of data are known as data miners.

Detailed explanation-2: -A logical data warehouse (LDW) is a data management architecture in which an architectural layer sits on top of a traditional data warehouse, enabling access to multiple, diverse data sources while appearing as one “logical” data source to users.

Detailed explanation-3: -Size:a data mart is typically less than 100 GB; a data warehouse is typically larger than 100 GB and often a terabyte or more. Range: a data mart is limited to a single focus for one line of business; a data warehouse is typically enterprise-wide and ranges across multiple areas.

Detailed explanation-4: -A data mart is a simple form of a data warehouse that is focused on a single subject (or functional area), hence they draw data from a limited number of sources such as sales, finance or marketing. Data marts are often built and controlled by a single department within an organization.

Detailed explanation-5: -Thus, the primary purpose of a data mart is to isolate-or partition-a smaller set of data from a whole to provide easier data access for the end consumers. A data mart can be created from an existing data warehouse-the top-down approach-or from other sources, such as internal operational systems or external data.