My former manager was a saavy manager and he wrote all the ETL procedures before he became the manager. He attended the Microsoft BI conference too

but it did not mean he learned anything.

The data came from different sources. He built a database for every source. So the ETL system had at least over 20 databases. After that, there was a staging database to group all the data together to build the dimension tables and then another database to build the real dimension table. Since there was no DBA in the company, so he could do anything he wanted. 😀