我们如何让 JPA EntityManager Flush 工作 [英] how we can get JPA EntityManager Flush work

问题描述

我的问题是为什么冲洗不起作用:

my question is why flush doesn't work :

public void ejbService(){
   Customer c = em.find(Customer.class,1);
   c.setName("newName");
   em.flush();
   //at this point when I query mysql table I can not see "newName"


   thread.sleep(10000);

   c.setName("anotherName");
}

完成该方法后，我在数据库中看到anotherName"我也用 em.find(Customer.class,1,Lock.None);但还是不行

After finishing the method I see "anotherName" in the db also I check it with em.find(Customer.class,1,Lock.None); but still not work

RGDS

推荐答案

您正在刷新，但没有提交 - 或者以其他方式结束可能配置为自动提交的事务/会话.

You're flushing, but you're not committing - or otherwise ending the transaction / session which is likely configured for auto-commit.

是的，在调用 flush() 之后，DBMS 现在知道您的数据 - 但按照 ACID 标准，在 DBMS 被告知提交数据之前，其他数据库会话都不会看到这些数据.

Yes, after calling flush(), the DBMS is now aware of your data - but following ACID standards, no other database sessions will see this data until the DBMS is told to commit it.

在不了解应用程序其余部分背后架构的其他详细信息的情况下，您可能希望执行以下操作:

Without knowing additional details about the architecture behind the rest of your application, etc., you're probably looking to do something like:

em.getTransaction().commit();

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