As you know a data warehouse is a platform for business intelligence.
There are two approaches to build a data warehouse:
1. Kimball approach
In this approach, you store the data in dimensional models, it helps you to have faster, user-understandable, and resilient to change data warehouse. Also, you can use OLTP or OLAP databases as your storage.
2. Inmon approach
In this approach, you store the data in third normal form, it helps us to handle high-volume databases, yet it is not fast, user-understandable, and resilient to change. Moreover you can not use an OLAP database as your ODS storage.