bmc_hub/migrations/999_fix_cvr_unique_constraint.sql

-- Migration: Remove the legacy CVR uniqueness rule.
-- CVR is company metadata and multiple e-conomic customer records may
-- legitimately share the same value. This mirrors migration 1000 and keeps
-- this historical migration safe when schema detection selects it again.

-- Drop old unique constraint
ALTER TABLE customers DROP CONSTRAINT IF EXISTS customers_cvr_number_key;

DROP INDEX IF EXISTS customers_cvr_number_unique_idx;

CREATE INDEX IF NOT EXISTS idx_customers_cvr
    ON customers(cvr_number)
    WHERE cvr_number IS NOT NULL AND cvr_number <> '';

COMMENT ON COLUMN customers.cvr_number IS
    'Danish CVR number. Informational/searchable; duplicates are allowed.';