A data lake is a centralized storage environment that keeps large volumes of raw data in its original form until it is needed. Unlike a traditional database or data warehouse, it can store structured data such as tables alongside semi-structured and unstructured data, including logs, documents, images, and video. Data is typically organized with metadata so it can be discovered and processed later.
Data lakes are useful when organizations need to retain diverse datasets for analytics, machine learning, or future use without defining every requirement in advance. For example, a retailer can collect customer activity, transaction records, and website logs in one lake for later analysis. Related concepts include data warehouse, data lakehouse, ETL, and data governance.
