Data Science Fundamentals

A data lake is a storage repository that holds raw data in its native, unprocessed format until it is needed, allowing flexibility for later use in various analytics. A data warehouse, by contrast, stores data that has already been cleaned, transformed, and structured (scrubbed) to fit a predefined schema, making it ready for specific reporting and analysis. This raw-versus-processed distinction is the fundamental difference between the two storage models, not the origin of the data (internal vs. external) or a simple structured/unstructured labeling of the whole system.