Network segmentation lays the foundation for the most effective database security programs. It can take a long time to implement a carefully planned security program blanketed across hundreds or even thousands of databases. By segmenting the network and compartmentalizing data by criticality, you can effectively perform a database security triage to put other compensating controls around the most important data. Good segmentation can actually help grease the skids in preparation for more advanced database security measures because the hardest part of locking down the most critical data is figuring out where it resides.”]
Source: https://www.darkreading.com/database-security/sound-database-security-starts-with-segmentation