在Hibernate中需要在运行时将类映射到不同的数据库

Question

I have MainDB database and unknown number (at compile time) of UserDB_1 , ..., UserDB_N databases. MainDB contains names of those UserDB databases in some table (new UserDB can be created at runtime).

All UserDB have exactly the same table names and fields.

How to handle such situation in Hibernate? (database structure cannot be changed).

Currently I am planning to create generic User classes not mapped to anything and just use native SQL for all queries:

session.createSQLQuery("select * from " + db + ".user where id=1")
    .setResultTransformer(Transformers.aliasToBean(User.class));

Is there anything better I can do? Ideally I would want to have mappings for UserDB tables and relations and use HQL on required database.

Answer 1

You specify the database when building your SessionFactory (via the connection string of the DataSource ). When you want to use another database, simply rebuild the SessionFactory with the new DataSource .

Answer 2

声明并注入不同的SessionFactory （每个数据库一个）。

Answer 3

Read this article on Hibernate blog: http://in.relation.to/Bloggers/MultitenancyInHibernate

Steve says that it is better to use a ConnectionProvider than separate SessionFactory.

Remember to disable second level cache.