This Guidance shows customers three different models for handling multi-tenancy in the database tier, each offering a trade-off between tenant isolation and cost and complexity. Tenant isolation is fundamental to the design and development of multi-tenancy applications, particularly software as a service (SaaS) applications. In a multi-tenant architecture, multiple instances of an application operate in a shared environment to achieve cost and operational efficiency. An application operator must safeguard tenant data by making sure it is accessible only to that particular tenant. By offering three models of tenant isolation at the database-level, this Guidance allows customers to choose the right architecture that meets their risk and cost requirements.

https://aws.amazon.com/solutions/guidance/multi-tenant-architectures-on-aws/?did=sl_card&trk=sl_card