If I’m using an ORM like JPA2 – where I have my entities that are mapped to my database, should I still be using a DAO? It seems like a lot more overhead. It is. And clearly, Java EE doesn’t encourage using the DAO pattern when using JPA (JPA already provides a standardized implementation of … Read more
You’re facing a limitation of Access SQL text parameters. They can not accommodate string values longer than 255 characters. Here is a simple example which demonstrates the problem. Dim db As DAO.Database Dim qdf As DAO.QueryDef Dim strUpdate As String Dim strLongString As String strLongString = String(300, “x”) strUpdate = “UPDATE tblFoo SET memo_field = … Read more
here’s mine @Component public class Dao{ @Resource(name = “sessionFactory”) private SessionFactory sessionFactory; public <T> T save(final T o){ return (T) sessionFactory.getCurrentSession().save(o); } public void delete(final Object object){ sessionFactory.getCurrentSession().delete(object); } /***/ public <T> T get(final Class<T> type, final Long id){ return (T) sessionFactory.getCurrentSession().get(type, id); } /***/ public <T> T merge(final T o) { return (T) sessionFactory.getCurrentSession().merge(o); … Read more
A DAO should provide access to a single related source of data and, depending on how complicated your business model, will return either full fledged Business objects, or simple Data objects. Either way, the DAO methods should reflect the database somewhat closely. A Service can provide a higher level interface to not only process your … Read more
using hibernate or JPA annotations: class User { @Enumerated(EnumType.STRING) UserType type } UserType is just a standard java 5 enum. I can’t imagine this is just limited to just annotations but I don’t actually know how to do this with hbm files. It may be very version dependant, I’m guessing but I’m pretty sure that … Read more
Your example terms; DataMapper, DAO, DataTableGateway and Repository, all have a similar purpose (when I use one, I expect to get back a Customer object), but different intent/meaning and resulting implementation. A Repository “acts like a collection, except with more elaborate querying capability” [Evans, Domain Driven Design] and may be considered as an “objects in … Read more
IMHO the transactions should go to service layer. Typically one business transaction consists of several queries and updates. If you place @Transactional only on DAO layer, each query and update will run in a separate transaction, which effectively defeats the purpose of transactions. But if services are @Transactional, each database interaction joins one main transaction … Read more
Changed in gradle from this: kapt “androidx.room:room-compiler:$roomVersion” to this: annotationProcessor “androidx.room:room-compiler:$room_version”
You can also try this code. It will preserve the items’ filetypes (.bas, .cls, .frm) Remember to refer to / Check the Microsoft Visual Basic For Applications Extensibility Library in VBE > Tools > References Public Sub ExportAllCode() Dim c As VBComponent Dim Sfx As String For Each c In Application.VBE.VBProjects(1).VBComponents Select Case c.Type Case … Read more
Use merge(). The exception means that the current session is already aware of the entity you are passing. If not, check how you have overridden hashCode() and equals() – it should return different values for different entities.