Perssimistic locking in MikroORM

01-pessimistic-lock-write.ts

await em.transactional(async _em => {
  await _em.findOne(Author, id, { lockMode: LockMode.PESSIMISTIC_WRITE });
});

// START TRANSACTION
// SELECT `e0`.* FROM `author` AS `e0` WHERE `e0`.`id` = ? FOR UPDATE
// COMMIT

02-pessimistic-lock-read.ts

const author = orm.em.findOne(Author, id);
// ...
await orm.em.transactional(async em => {
  await em.lock(author, LockMode.PESSIMISTIC_READ);
});

// SELECT `e0`.* FROM `author` AS `e0` WHERE `e0`.`id` = ?
// START TRANSACTION
// SELECT 1 FROM `author` AS `e0` WHERE `e0`.`id` = ? LOCK IN SHARE MODE
// COMMIT