-- CVR is company metadata, not an external customer identity. Multiple
-- e-conomic customer records may legitimately share the same CVR number.
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.';