11.3.3. Detached objects and automatic versioning

Each interaction with the persistent store occurs in a new Session. However, the same persistent instances are reused for each interaction with the database. The application manipulates the state of detached instances originally loaded in another Session and then reattaches them using Session.update(), Session.saveOrUpdate(), or Session.merge().

// foo is an instance loaded by a previous Session
foo.setProperty("bar");
session = factory.openSession();
Transaction t = session.beginTransaction();
session.saveOrUpdate(foo); // Use merge() if "foo" might have been loaded already
t.commit();
session.close();

// foo is an instance loaded by a previous Session
foo.setProperty("bar");
session = factory.openSession();
Transaction t = session.beginTransaction();
session.saveOrUpdate(foo); // Use merge() if "foo" might have been loaded already
t.commit();
session.close();

Copy to Clipboard

Toggle word wrap

Again, Hibernate will check instance versions during flush, throwing an exception if conflicting updates occurred.

You can also call lock() instead of update(), and use LockMode.READ (performing a version check and bypassing all caches) if you are sure that the object has not been modified.

返回顶部

此内容没有您所选择的语言版本。

11.3.3. Detached objects and automatic versioning

学习

尝试、购买和销售

社区

关于红帽文档

让开源更具包容性

關於紅帽

Theme

Red Hat legal and privacy links

Red Hat legal and privacy links