One reason that RDBMS has retained popularity is that it’s established technology, well understood and has a standard language (SQL) that multiple vendors support. It also has a few good interfaces like ODBC and JDBC that make it connect with different languages pretty well. A stable API is a strong factor in keeping a technology … Read more
You could use a projection: Criteria criteria = session .createCriteria(Person.class) .setProjection(Projections.max(“age”)); Integer maxAge = (Integer)criteria.uniqueResult();
You could override the save method. class MyModel(mongoengine.Document): creation_date = mongo.DateTimeField() modified_date = mongo.DateTimeField(default=datetime.datetime.now) def save(self, *args, **kwargs): if not self.creation_date: self.creation_date = datetime.datetime.now() self.modified_date = datetime.datetime.now() return super(MyModel, self).save(*args, **kwargs)
Hibernate 5 fixes this issue and now the dirty checking for a setter looks like this: public void $$_hibernate_write_title(String paramString) { if (!EqualsHelper.areEqual(this.title, paramString)) { $$_hibernate_trackChange(“title”); } this.title = paramString; } public void $$_hibernate_trackChange(String paramString) { if (this.$$_hibernate_tracker == null) { this.$$_hibernate_tracker = new SimpleFieldTracker(); } this.$$_hibernate_tracker.add(paramString); } So, the solution is an upgrade to … Read more
NHibernate may be more mature. That does not necessarily mean it is a “better” solution. Having used it at my job for some time, I would personally prefer to use almost anything than NHibernate (even straight SQL, if migration were remotely feasible). The number of error messages thrown by NHibernate that don’t mean anything (or … Read more
I haven’t used SQLAlchemy much so I figured I’d give it a shot. I didn’t try to use your models, I just wrote some new ones (similar enough though): likes = db.Table(‘likes’, db.Column(‘user_id’, db.Integer, db.ForeignKey(‘user.id’)), db.Column(‘post_id’, db.Integer, db.ForeignKey(‘post.id’)) ) class User(db.Model): id = db.Column(db.Integer, primary_key=True) username = db.Column(db.String(20)) def __repr__(self): return “<User(‘%s’)>” % self.username class … Read more
Marco Cantu is a big believer in InstantObjects: Home Others include DObject: http://www.macrobject.com/en/dobject/ and tiOPF http://tiopf.sourceforge.net/Doc/overview/index.shtml You also might be interested in the G Framework: http://code.google.com/p/g-framework/
As mentioned in a different answer to the question referenced previously, the following HQL construct works for me: select o from Product o WHERE :value is null or o.category = :value if :value is passed in as null, all Products are returned. See also Optional or Null Parameters Note that this won’t work in some … Read more