37signals-multi-tenant

URL-based multi-tenancy in Rails is implemented by enforcing an account_id on every table, using UUIDs for primary keys, and routing requests through a per-request Current context to isolate data per account within a single database.

Data isolation per account in a single database is achieved by scoping all queries through a Current context that sets Current.account and Current.user per request, ensuring every resource is restricted to its account.

Current context works by initializing Current.account from the URL path on each request, allowing account-aware routing, controllers, and models to automatically restrict resource access to the active account.

UUIDs for primary keys are used in this multi-tenant approach to ensure unique identifiers across all accounts within the single database, preventing collision and maintaining secure data isolation.

Account-scoped queries support admin panels, SaaS apps, and collaboration tools by using Account and Membership models for per-account access control and role management, keeping resources restricted to an account.

URL-based multi-tenancy with a single database requires enforcing account_id on every table and routing through account context, which may not suit applications needing physical database separation per tenant.