This illustration shows the four key differences between OLTP systems and a data warehouse:

1. The OLTP has few Indexes, while a data warehouse has many.
2. The OLTP has many Joins, while a data warehouse has some.
3. The OLTP's Duplicated Data are Normalized DBMS, and Denormalized DBMS in a data warehouse.
4. Derived Data and Aggregates are Rare in OLTP, but Common in a data warehouse.