Before files can be uploaded to the DWH, it is often the case that the heterogeneous information is translated into a uniform presentation form. A DWH is supplied from the company’s internal data sources
as well as from relevant external ones too. Internal data: Operating systems: Enterprise Resource Planning systems (ERP), Customer Relationship Management
systems (CRM); operating databases; Content Management Systems (CMS);flat files (e.g., Excel,
CSV, Text files), emails, etc. External data: Applications
and systems from external service providers, websites, social media, cloud services, etc.
