No row with the given identifier exists

在为已建的表添加一个字段，因为我要用一个自动脚本工具生成bean类，hibernate和ibatis的相关配置文件，所以按以往的做法把表删掉然后用重建表。

最后JBPM的实例表，变量表与该文档绑定了ID导致如下面类似的错误：

Hibernate:No row with the given identifier exists

ObjectNotFoundException: No row with the given identifier exists

Where it can occur:

This might occur if you try to load a non-proxied object with session.load() or you load a proxied object and later access the proxy. It may also occur when loading mapped collections which are not eagerly fetched.

What it means:

This means just what it says - Hibernate expected to have a row with a certain id in the database, and did however not find it.

How it can be caused:

Wrong id for load

If you are using a nonexistant id for a load(), you will get this exception. Note that if you are using proxies, this may occur later on, when the proxy is first "broken".

Broken foreign key relationships

If you map for example a many-to-one relationship, and the table containing the objects on the "many" side contains a foreign key to a non-existant row of the "one" side table, you will get such an exception. This will only happen if the collection is not fetched eagerly.

Reusing a session across multiple transactions

The hibernate session internally memorizes some state. For example it internally stores ids which it assumes are already deleted from the database. So if you make the session believe somehow an object with a certain id has been deleted, and later try to load it again, you will get this exception without Hibernate even trying to access the database. So be careful with that.

How it can be fixed:

• Check the ids you are using for load
• Validate your foreign key relationships - the database should already maintain such integrity constraints.
• Beware of multiple transactions within a single session. Try to stick to "one session, one transaction" rule. Especially do not reuse sessions after an HibernateException.

也就是是说关系数据库一致性遭到了破坏，找到相关表，就可以解决了。