ALTER TABLE "licenses"
ADD COLUMN "default_duration_days" INTEGER DEFAULT 365;

UPDATE "licenses"
SET "default_duration_days" = 365
WHERE "default_duration_days" IS NULL;

UPDATE "user_licenses"
SET "expires_at" = "starts_at" + INTERVAL '365 days'
WHERE "expires_at" IS NULL;

COMMENT ON COLUMN "licenses"."default_duration_days" IS '사용자에게 라이선스를 부여할 때 기본 적용할 기간(일). NULL이면 무기한.';