Yeah, that's the question :) On Sat, Sep 20, 2008 at 4:47 PM, Ken Egozi <[EMAIL PROTECTED]> wrote:
> 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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