-- 084_multi_code_per_agent.sql
-- Allow a single sales agent (person/company) to have MULTIPLE referral codes,
-- each with its own client discount and agent commission split.
--
-- Background: each sales_agents row already represents one referral code
-- (it owns a unique agent_code and links to one discount_code). The only thing
-- that blocked the same person from having several codes was the UNIQUE
-- constraint on sales_agents.email. We drop that constraint (keeping a plain
-- index for lookups) so the same email can back several codes/splits.
--
-- All commission/referral lookups key on the unique agent_code, so no other
-- logic changes are required at the DB level.

BEGIN;

-- Drop the UNIQUE constraint on email (name is auto-generated by Postgres).
ALTER TABLE sales_agents DROP CONSTRAINT IF EXISTS sales_agents_email_key;

-- Keep a non-unique index so email lookups stay fast.
-- (idx_agents_email already exists from migration 011; create defensively.)
CREATE INDEX IF NOT EXISTS idx_agents_email ON sales_agents (email);

COMMIT;