NH is actually two things. 1. an OR/M 2. a very smart DAL you can have entity model that reflects the DB's E/R in a 1:1 manner, without relations and collections, just primitive properties, and still enjoy the merits of NH (PI, Caches, efficient connection management, smart query capabilities).
but what's the fun in that? On Sat, Sep 20, 2008 at 4:34 PM, Gustavo Ringel <[EMAIL PROTECTED]>wrote: > You may work without collections. > > If you have Order and OrderLine...you can query OrderLines doing something > like > "from OrderLine orderLine where orderLine.Order = :order" > > and you have the collection your self... > > You lose the option of encapsulating every call to order lines using the > repository for orders something you rarely want to lose. > You are giving a lot of info to the user now...using the option os mapping > the collection you can tell him how many order lines he has even without > knowledge of the order lines structure (you can map it with access = field > and hide it) > > for sure you have now to decide how to fetch the order lines in code while > putting order lines inside the order will give you the option to change the > fetching in mapping and using HQL or criteria... > > In resume you can work without mapping the collections...mapping big > collections is not a good practice so lot of times we are not mapping > collections where it is possible...but i don't think you have to set an > strategy working with or without them...you should use it or not depending > on your needs > > A rule of thumb one Fabio gave me: if you cannot map it with lazy=false > then it is not a good candidate to be inside the class... > > Gustavo. > > > On Sat, Sep 20, 2008 at 2:40 PM, N. D. <[EMAIL PROTECTED]> wrote: > >> Thanks Gustavo, you are right that i'm referring only to the mapping >> collections aspects of NH, i'm pretty much satisfied with everything else. >> when i think about it a bit more, the essence of the question is - if i >> don't use collection mapping at all and just work manually setting Ids - can >> you list the "good things" i lose? >> >> >> >> >> On Sat, Sep 20, 2008 at 3:35 PM, Gustavo Ringel <[EMAIL PROTECTED] >> > wrote: >> >>> Hi >>> >>> Regarding >>> >>> 1) NH is a PI framework, it will achieve it goals letting you to do same >>> things as you will do in the language without persistence. >>> >>> There is no magic in C# or Java that will give you a way to set only one >>> side of the collection and the other one will magically appear. >>> >>> 2) I don't see what the worry about with the cascade action is you must >>> write it in the mapping if you need it and you may not write it if you >>> don't...the same applies for opening a FK in a DB >>> >>> 3) The problem is not extra SQL the problem is which side is in charge of >>> the persistence. >>> >>> 4) You are using an advanced ORM because you want things like lazy >>> loading, you don't need to worry about them you can set default = false and >>> live in the old days without lazy loading...you use it because you know you >>> need it, it's not NH which will force you to use it and it won't decide to >>> you what's lazy or what not like SQL does not decide if you bring a joing >>> between two databases with a join or a select and a after that running with >>> a CURSOR... >>> >>> 5) many-to-many relations sometimes are really cruel...i try to avoid >>> them if i can. >>> >>> >>> Regarding the conclusion, you talked about thinks you consider >>> problematic mapping collections and then ask if NH only advantage is only on >>> querying, i don't think mapping a collection is even 0.01% of what the >>> framework brings... >>> >>> Gustavo. >>> >>> >>> On Sat, Sep 20, 2008 at 2:08 PM, ndotan <[EMAIL PROTECTED]> wrote: >>> >>>> >>>> Hey all, >>>> I have a theoretical question.i fail to see how nhibernate makes life >>>> easy for me by mapping relations. >>>> >>>> Every way i look at it, it seems that it poses more work to the >>>> programmer. >>>> for example taking directly from the documentation: >>>> >>>> >>>> http://www.hibernate.org/hib_docs/nhibernate/html/example-parentchild.html >>>> >>>> Parent p = (Parent) session.Load(typeof(Parent), pid); >>>> Child c = new Child(); >>>> c.Parent = p; >>>> p.Children.Add(c); >>>> session.Save(c); >>>> >>>> 1. I need to maintain both edges of the link myself, >>>> 2. i need to worry about cascade action >>>> 3. i need to worry about the extra sql that is generated if i do not >>>> use inverse=true >>>> 4. i need to worry about when to use lazy loading. >>>> 5. in many to many relations, i need to worry twice as much. >>>> >>>> so is the only advantage in the querying? and if so, i imagine that >>>> most of the queries would be done in HQL and i could just do a join >>>> for the relations by hand. >>>> >>>> >>>> i feel im missing a point. >>>> >>>> thanks. >>>> >>>> >>>> >>> >>> >>> >> >> >> > > > > -- Ken Egozi. http://www.kenegozi.com/blog http://www.musicglue.com http://www.castleproject.org http://www.gotfriends.co.il --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "nhusers" group. 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