Top-Down architecture of Warehouse development

What is Top-Down architecture of Warehouse development?

The interaction associated with the architecture begins with an Extraction, Transformation, Migration, and Loading (ETML) process working from legacy and/or external data sources. Extraction transformation, and migration, process data from these sources and output it to a centralized Data Staging Area. Following this, data and metadata are loaded into the Enterprise Data Warehouse and the centralized metadata repository. Once these are constituted, Data Marts are created from summarized data warehouse data and metadata.