Perdatabase

Perdatabase is a design approach in which configuration, policy, or resource settings are applied at the database level rather than at the instance or server level. It is commonly used in multi-tenant database environments and database-as-a-service platforms to provide isolation and customization for individual databases.

In a perdatabase model, each database can have its own security settings, backup schedules, maintenance windows, connection limits, and resource quotas. This enables tenants or applications to tailor policies to their needs without affecting other databases within the same system. Per-database policies may cover access control, encryption keys, auditing rules, schema versions, and retention policies, allowing finer-grained control than global, instance-level settings.

Advantages of the perdatabase approach include stronger data isolation, easier compliance with regulatory requirements, and the ability to customize behavior for different workloads. It can also simplify fault containment, since an issue in one database is less likely to impact others. However, it can introduce administrative overhead and complexity, as administrators must manage policies for many databases, and cross-database operations may become more limited or require specialized tooling. Performance and scaling considerations may arise, as per-database quotas and monitoring need to be maintained separately.

Perdatabase is often contrasted with per-schema or per-table configurations, which apply even more granularly within a single database. Its applicability varies by platform and architecture, and the term may be used differently across systems. See also multi-tenant architectures, per-tenant database design, and database isolation.