LINQ and QueryOver are completely different query methods, which are added to the ones that existed in NHibernate 2 (Criteria, HQL, SQL) QueryOver is meant as a strongly-typed version of Criteria, and supports mostly the same constructs, which are NHibernate-specific. LINQ is a “standard” query method, which means the client code can work on IQueryable … Read more
The new Linq provider does it a little differently: var customers = session.Query<Customer>().Fetch(c => c.Orders).ToList(); More here: http://mikehadlow.blogspot.com/2010/08/nhibernate-linq-eager-fetching.html
I would claim that, like most things, its a sliding scale. There are things that we make that want to have the property of persistence. On one end of the scale is this thing having all of the guts, dependencies, and code that is custom built to persist just this one thing in its particular … Read more
While similar names, the usage is different. I. Projections.distinct(Projections.property(“id”)); this statement would be translated into SQL Statement. It will be passed to DB Engine and executed as a SQL DISTINCT. See: 17.9. Projections, aggregation and grouping so e.g. this example: List results = session.createCriteria(Cat.class) .setProjection( Projections.projectionList() .add( Projections.distinct(Projections.property(“id”)) ) ) .list(); would seems like: SELECT … Read more
NHibernate is an ORM, or Object-Relational Mapper. In the same line as LINQ to SQL, Entity Framework, LLBLGen, and others, ORM tools remove most of the need to write stored procedures to handle common data access (CRUD) for your business objects. ORM tools require that you create (either manually or with a visual designer…depends on … Read more
Recommendation is that you should just have one DTO class for each entity suffixed with DTO e.g. CustomerEntryDTO for the Customer entity (but you can certainly use inheritance hierarchies as per choice and requirements). Moreover, Add a abstract DTOBase kind of base class or an interface; and do not use such deep inheritance heirarchies for … Read more
[UPDATE] Please see the following links for a version of that uses RealProxy to proxy the SqlCommand – batching is now supported blog http://blog.fearofaflatplanet.me.uk/mvcminiprofiler-and-nhibernate-take-2 gist https://gist.github.com/1110153 I’ve left the original answer unaltered as it was accepted. [/UPDATE] I’ve managed to partially get this to work by implementing a Profiled Client Driver (example for Sql Server … Read more
Ok, I found the answer. Add the not-found=”ignore” attribute to the property KeyField: <many-to-one name=”KeyField” not-found=”ignore” class=”Model.Entities.Key, Model” column=”field_id” />
If you’re using the ICriteria API, you need: .SetResultTransformer(new DistinctEntityRootTransformer()) If you’re using the QueryOver API, you need: .TransformUsing(Transformers.DistinctRootEntity) But beware, this all occurs on client side, so all the duplicate rows are still pulled from SQL database.
You could use the NHibernate Disjunction class to do this in a more elegant (IMHO) fashion: var disjunction= new Disjunction(); disjunction.Add(Restrictions.On<Type>(e => e.Code).IsLike(codePart)); disjunction.Add(Restrictions.On<Type>(e => e.Description).IsLike(codePart)); //(and so on) and then: query.Where(disjunction) Each “OR” is a separate instruction, which helps if you want to add the predicates conditionally.