A Database is a collection of data that is organized for storage, accessibility, and retrieval. This is mainly used for supporting the operational data of current data. Because the purpose of a Database is to capture and maintain data the schema with which it is stored is Flat Relational. Whereas, a data warehouse is a place where a huge amount of data is stored from disparate and multiple sources.
This is extremely important for data analysis and decision-making. Because the data stored is historical and current, the data must be integrated from multiple systems, therefore a multidimensional scheme is required.