persistence

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Closed . This question is opinion-based. It is not currently accepting answers. Learn more . Want to improve this question? Update the question so it can be answered with facts and citations by editing this post . In the last time I heard a lot of complaining about hibernate. And indeed I have some painful experiences with hibernate too. So I read about Ebean and Siena . Both have interesting approaches. Unfortunately, database access layers are very easy to write, but if your project grows and you have to handle great database-tables, you know if they are good or not. So it's really difficult

I'm currently working on a project that requires EntityManager EntityManagerFacotry and Persistence each from the javax.persistence package. It seems to be for the database service, but the current code is not very well documented. By searching google it seems that there should be an xml file that comes along with this, but there isn't one of those either. I guess my question is simply how do I make these unresolved imports go away? Do I have to add another jar to the build path? It seems that I shouldn't have to since it's been around since 1.5. Any help is greatly appreciated. Karthik Reddy

I have a legacy database, which I am using EJB3 to model. The database is in quite a poor shape, and we have certain unusual restrictions on how we insert into the DB. Now I want to model the database in a hierarchy that fits in with the DB strucuture, but I want to be able to manually insert each entity individually without the persistence manager trying to persist the entities children. I am trying something like the following (boilerplate left out): @Entity @Table(name = "PARENT_TABLE") public class Parent { @Id @Column(name = "ID") int id; @OneToMany List<Child> children; } @Entity @Table

I have a large Python dictionary of vectors (150k vectors, 10k dimensions each) of float numbers that can't be loaded into memory, so I have to use one of the two methods for storing this on disk and retrieving specific vectors when appropriate. The vectors will be created and stored once, but might be read many (thousands of) times -- so it is really important to have efficient reading. After some tests with shelve module, I tend to believe that sqlite will be a better option for this kind of task, but before I start writing code I would like to hear some more opinions on this... For example,