persist « dao « Java Database Q&A

1. Java - DAO Layer or Plugin

I work on the JBJF Project on SourceForge and we want to improve on the Database Access for this framework. Currently, it's semi-flexible, but the access is done at the ...

2. Should persistence logic be placed in domain model beans or in DAOs only?

Could please anybody explain what are pros and cons of this? I mean, without using ORM framework/JPA specification. It concerns many-to-many and many-to-one relationships between entities. Imagine entity relationship

teacher ...

3. Should em.flush be used in EJB 3.0 DAOs to abstract persistence layer?

Say I have following generic dao deployed as a local SLSB:

public interface CrudService {

public <T> T create(T t);

public <T> T find(Object id, Class<T> type);

public <T> T update(T t);

public void delete(Object t);

public ...

4. Roll yer own DAO vs. XML-based persistence layer

The kind of transparent persistence technology in JDO has existed since the mid-1980s in C++. JDO has the sole purpose of providing transparent persistence for Java object models. It was not developed as a reaction to EJB. We started JDO in 1999, based on earlier Java persistence efforts in the ODMG, long before EJB existed.