ALTER TABLE file_files
  ADD COLUMN preview_mime_type VARCHAR(255) NULL AFTER thumbnail_etag,
  ADD COLUMN preview_size_bytes BIGINT UNSIGNED NULL AFTER preview_mime_type,
  ADD COLUMN preview_bucket VARCHAR(128) NULL AFTER preview_size_bytes,
  ADD COLUMN preview_object_key VARCHAR(512) NULL AFTER preview_bucket,
  ADD COLUMN preview_object_version VARCHAR(128) NULL AFTER preview_object_key,
  ADD COLUMN preview_etag VARCHAR(128) NULL AFTER preview_object_version,
  ADD UNIQUE KEY uq_file_files_preview_object_key (preview_object_key);