使用Hibernate进行内容比较以实现版本控制功能的最佳方法是什么？

Question

I'm working on a JSF based web application with backing beans and Hibernate for persistence.

The goal is to implement a feature to compare changes across versions, where some attributes are from "foreign key" objects. In order to get a generic solution, the best way would be to create a kind of database trigger or something.

I know about the @Version annotation, but I don't want only to have a history about the persisted object, but also the associated object.

Anyone already done something like that?

Edit: To specify the question here is more detail information. The application have a lot of business objects, most of them just have simple text attributes like Strings. The main thing the application do is CRUD. I would like to build a feature where users can compare versions older versions of a business object. My first idea was just to have a version column in the tables of the business objects and to save always a new dataset with a new version. But this seems for me like a large overload, to save everything duplicated. And how to keep the associations between versioned objects? Is there an other, lighter aprroach for that? This approach would also imply to change every single database access class and save method.

Answer 1

I would solve the problem like this:

• business object table, example: EXAMPLE_TABLE

   ----------------------------------- |ID |column 1|column 2|...| |---------------------------------- |1 |foo |bar |...| |2 |baz |test |...| |... |... |... |...| ----------------------------------- 

• history preservation table for each business object table, example: EXAMPLE_TABLE_HISTORY

   ------------------------------------------------ |ID |column 1|column 2|...|version|date| |----------------------------------------------- |1 |null |foo |...|1 | | |1 |baz |test |...|2 | | |... |... |... |...|... |... | ------------------------------------------------ 

You can define database-triggers for EXAMPLE_TABLE on each operation (INSERT, UPDATE or DELETE) to copy the current data from EXAMPLE_TABLE to EXAMPLE_TABLE_HISTORY including a version (Column version ) and a timestamp (Column date ) to preserve a history.

Advantages:

• You can easily retrieve all versions of your business object using the ID column in the history preservation table.
• Using triggers you don't have to change your application-code.

Answer 2

I think I found what I'm looking for. Event though I wanted to solve it with db triggers, hibernate provides a pretty solution. Hibernate envers creates an audit table for each versioned/annotated entity. All you have to do is to set the annotations in auditable entities. The needed tables will be generated and also the history of related audited entities will be managed. So you can recreate the whole content of your entities.