RLS — Row-Level Security

Definition

Database-enforced filtering of rows by tenant/project: even a buggy application query cannot return another tenant's data, because the database itself refuses.

Worked Example

Policy sketch:

CREATE POLICY tenant_isolation ON cost_items
  USING (tenant_id = current_setting('app.tenant_id')::uuid);

A SELECT without the right tenant context returns zero rows —
regardless of what the application code asked for.

Interpretation & Pitfalls

RLS is defense in depth: application-layer checks fail; the database backstop holds.

In TupicFinance

RLS policies run across the database tables as part of the platform's layered security model.