关于save和persist

最新推荐文章于 2021-03-02 20:34:32 发布

最新推荐文章于 2021-03-02 20:34:32 发布 · 92 阅读

本文对比分析了persist()和save()两种持久化方法的特点及适用场景。persist()保证实例持久化但不立即分配标识符，适用于长会话；save()则立即返回标识符并可能即时执行插入操作。

persist() is well defined. It makes a transient instance persistent. However, it doesn't guarantee that the identifier value will be assigned to the persistent instance immediately, the assignment might happen at flush time. The spec doesn't say that, which is the problem I have with persist().

persist() also guarantees that it will not execute an INSERT statement if it is called outside of transaction boundaries. This is useful in long-running conversations with an extended Session/persistence context.

A method like persist() is required.

save() does not guarantee the same, it returns an identifier, and if an INSERT has to be executed to get the identifier (e.g. "identity" generator, not "sequence"), this INSERT happens immediately, no matter if you are inside or outside of a transaction. This is not good in a long-running conversation with an extended Session/persistence context."