vaultwarden/migrations/mysql/2018-05-25-232323_update_attachments_reference/up.sql

ALTER TABLE attachments RENAME TO oldAttachments;

CREATE TABLE attachments (
  id          VARCHAR(40) NOT NULL PRIMARY KEY,
  cipher_uuid VARCHAR(40) NOT NULL REFERENCES ciphers (uuid),
  file_name   TEXT    NOT NULL,
  file_size   INTEGER NOT NULL

);

INSERT INTO attachments (id, cipher_uuid, file_name, file_size) 
SELECT id, cipher_uuid, file_name, file_size FROM oldAttachments;

DROP TABLE oldAttachments;