Plugin - Uni Ecto

# config/config.exs config :uni_ecto_plugin, :cache, enabled: true, ttl: :timer.hours(1) The plugin will cache the list of valid tenants in an ETS table. Validating a prefix becomes an O(1) memory read instead of a SQL query. 1. The "Prefix Not Set" Error Error: (Ecto.NoResultsError) expected query to return a prefix, but none was set Fix: Ensure your TenantResolver plug runs before any database calls in your controller pipeline. 2. Association Loading Fails If you have a belongs_to across schemas, Ecto may struggle with prefixes. Fix: Define associations with explicit prefixes or use Repo.assoc with the tenant prefix manually.

| Library | Strategy | Best For | | :--- | :--- | :--- | | | PostgreSQL Schemas | Most Elixir SaaS apps (Gold standard) | | Uni Ecto Plugin | Custom (Configurable) | Developers needing fine-grained control | | Apartment (Rails) | Row-level (Legacy) | Not recommended for Elixir | | Ash Framework Multi-Tenancy | Resource Layer | Large, complex domain models | uni ecto plugin

defmodule MyApp.Repo do use Ecto.Repo, otp_app: :my_app use UniEcto.Plugin, prefix_key: :tenant_prefix def all_tenants do # Could be a DB query or a static list ["public", "tenant_customer_a", "tenant_customer_b"] end end Step 3: Generate the Tenant Migrations The plugin usually provides a generator: # config/config

In the modern landscape of Software as a Service (SaaS), multi-tenancy is no longer a luxury—it’s a necessity. Whether you are building a white-label CRM, an enterprise ERP, or a simple API for startups, you need a way to isolate customer data securely. The "Prefix Not Set" Error Error: (Ecto