MyEntity e = new MyEntity(); // scenario 1 // tran starts em.persist(e); e.setSomeField(someValue); // tran ends, and the row for someField is updated in the database // scenario 2 // tran starts e = new MyEntity(); em.merge(e); e.setSomeField(anotherValue); // tran ...
虽然如果连接到MySQL,merge()可以像使用ON DUPLICATE KEY UPDATE选项调用INSERT一样有效,但JPA是一个非常高级的编程,你不能认为这种情况在任何地方都是如此。 2019-01-03 祁澈盘哼颗 如果您使用的是已分配的生成器,则使用merge而不是persist会导致冗余的SQL语句,从而影响性能。 此外,为托管实体调用合并也是一个错误...
JPA EntityManager的四个主要方法 ——persist,merge,refresh和remove public void persist(Object entity) persist方法可以将实例转换为managed(托管)状态。在调用flush()方法或提交事物后,实例将会被插入到数据库中。 对不同状态下的实例A,persist会产生以下操作: 如果A是一个new状态的实体,它将会转为managed状态; ...
JPA EntityManager的四个主要方法 ——persist,merge,refresh和remove public void persist(Object entity) persist方法可以将实例转换为managed(托管)状态。在调用flush()方法或提交事物后,实例将会被插入到数据库中。 对不同状态下的实例A,persist会产生以下操作: 1.如果A是一个new状态的实体,它将会转为managed状态...
persist: Insert a new register to the database Attach the object to the entity manager. merge: Find an attached object with the same id and update it. If exists update and return the already attached object. If doesn't exist insert the new register to the database. persist() efficie...
<T> T merge(T entity) Merge the state of the given entity into the current persistence context.voidpersist(Object entity) Make an instance managed and persistent.voidrefresh(Object entity) Refresh the state of the instance from the database, overwriting changes made to the entity, if any...
persist()方法用于添加一条数据 //添加数据 @Test public void firstTest() { //通过工具类获得EntityTransaction对象 EntityManager entityManager = Jpautil.getEntityManager(); //获得事物对象 EntityTransaction transaction = entityManager.getTransaction(); ...
$vote->setValue($voteData['value']);$this->em->persist($vote);$this->em->flush($vote);returnnewJsonResponse($vote->toArray(),201); } 开发者ID:pdziok,项目名称:hackday-project,代码行数:26,代码来源:VoteController.php 示例5: insertUpdateProcessing ...
merge(job); } @Override public void delete(Job job) { entityManager.remove(job); } @Override public void deleteByJobId(String jobId) { entityManager.remove(findByJobId(jobId)); } @Override public void persistJob(Job job) { entityManager.persist(job); // this is causing javax.persistence...
$user = (newAuthorEntity())->setName($name)->setEmail('')->setPassword('')->setSubscribed(1)->setFacebookId($fbid)->setPublicationDate(new\DateTime())->setRole(1);$this->_em->persist($user);$this->_em->flush(); }