This document provides an overview of heterogeneous persistence and different database management systems (DBMS). It discusses why a single DBMS is often not sufficient and describes different types of DBMS including relational databases, key-value stores, and columnar databases. For each type, it outlines good and bad use cases, examples, considerations, and pros and cons. The document aims to help readers understand the different flavors of DBMS and how to choose the right ones for their specific data and access needs.