by default the column name is the property name.You can specify the column
name adding 'column' attribute or <column> tag.

2009/8/1 Everett Muniz <[email protected]>

> Thanks for the links Fabio.
> I've checked the links along with several similar references to the <id>
> tag on your blog.  I also went back and checked the NHibernate docs.
>
> If I'm understanding the docs and what you've written correctly, all that I
> need to exclude the POID property is omit the name attribute from the <id>
> tag.  What I'm still not getting is how the mapping knows the database
> column to use.  I guess the fact that the docs say the column attribute is
> optional is confusing me.
>
> Is there a convention in play here?  I mean, is the column name being
> inferred?  This blog entry,
> http://fabiomaulo.blogspot.com/2009/05/nhibernate-versioning.html, seems
> to suggest that the column name may be being inferred if I'm reading it
> right.
>
> On Sat, Aug 1, 2009 at 6:10 PM, Fabio Maulo <[email protected]> wrote:
>
>> ah... btw the entity UserMitaMita (of the previous mail) is the entity
>> persisted in the DB and does not have a property ID.
>> In that post who has the ID is exactly the in memory wellknow instance
>> (Country).
>>
>> 2009/8/1 Fabio Maulo <[email protected]>
>>
>> The post is for another stuff.
>>> What I'm saying you is that you can work without declaring a property to
>>> represent the POID in your entities.
>>> In my blog you can find other examples where I'm using an entity without
>>> the ID.
>>> This is another old post
>>> http://fabiomaulo.blogspot.com/2008/11/entities-behavior-injection.html
>>> There you can see an entity with ID and the Invoice entity without ID and
>>> with behaviour injected.
>>>
>>> 2009/8/1 Mike Nichols <[email protected]>
>>>
>>>
>>>> @Fabio,
>>>> This would only work if the values are static correct? I looked at
>>>> your blog post on this (http://fabiomaulo.blogspot.com/2009/08/from-db-
>>>> to-ram-wellknowinstancetype.html<http://fabiomaulo.blogspot.com/2009/08/from-db-%0Ato-ram-wellknowinstancetype.html>for
>>>>  those listening)
>>>> and while this is useful for those unchanging values like countries
>>>> and so on I am not sure how this could be applied here.
>>>>
>>>>
>>>>
>>>> On Jul 31, 9:03 pm, Fabio Maulo <[email protected]> wrote:
>>>> > In NH you can have an entity without the ID and the ID only for
>>>> persistence
>>>> > (without a private filed).In uNhAddIns or in my blog you can find
>>>> > various examples the last is:
>>>> > Entity:
>>>> > public class UserMitaMita
>>>> > {
>>>> > public virtual string Name { get; set; }
>>>> > public virtual Country Country { get; set; }}
>>>> >
>>>> > Mapping
>>>> > <class name="UserMitaMita">
>>>> > <id type="int">
>>>> > <generator class="hilo"/>
>>>> > </id>
>>>> > <property name="Name"/>
>>>> > <property name="Country" type="Country"/>
>>>> > </class>
>>>> >
>>>> > 2009/7/31 Everett Muniz <[email protected]>
>>>> >
>>>> >
>>>> >
>>>> > > For those of you doing DDD with NHibernate...
>>>> >
>>>> > > Is it pretty typical to run into scenarios where the way your value
>>>> objects
>>>> > > are used with the domain requires a class mapping with its attendant
>>>> <id>
>>>> > > requirement?  I guess what I'm asking is whether having to support
>>>> an ID
>>>> > > within my value object for the sake of persistence is just a fact of
>>>> life
>>>> > > related to the oft-lamented impedance mismatch between objects and
>>>> > > relational databases?  I know I can map the ID to a private field so
>>>> that
>>>> > > from the domain point-of-view it doesn't exist but it feels like
>>>> cruft in my
>>>> > > value object.  Before I just accept the compromise I wanted to see
>>>> if I'm
>>>> > > overlooking something.
>>>> >
>>>> > > If you care about the specific scenario that prompted the question
>>>> read on,
>>>> > > otherwise ignore the rest...
>>>> >
>>>> > > The system we're developing has all sorts of objects related to
>>>> drawing and
>>>> > > many have a color associated with them.  Sounds simple I know.  The
>>>> catch is
>>>> > > that the color actually used to draw an object in a given context is
>>>> > > determined by applying a strategy that often depends on the data
>>>> associated
>>>> > > with that drawing context.
>>>> >
>>>> > > So, any object that requires a color (some entities some value
>>>> objects) has
>>>> > > a Color property of type ColorSource.  ColorSource is an abstract
>>>> class with
>>>> > > several specializations such as ConstantColorSource and
>>>> > > SubstringColorSource.  These specializations are value objects.
>>>> > >  Any ConstantColorSource/SubstringColorSource instances with the
>>>> same
>>>> > > attributes are completely interchangable.
>>>> >
>>>> > > However, when it comes to the persistence mapping in NHibernate the
>>>> most
>>>> > > natural way to map the relationship of the various objects that
>>>> refer to a
>>>> > > ColorSource seems to be creating an independent class mapping for
>>>> > > ColorSource that employs the inheritance mapping features of
>>>> NHibernate.
>>>> > >  However, the class mapping approach seems to really depend on ID.
>>>>  As far
>>>> > > as I can tell NHibernate's answer to value objects is components but
>>>> I just
>>>> > > can't figure out how to accomplish the required mapping using
>>>> components w/o
>>>> > > a whole lot of duplication.
>>>> >
>>>> > --
>>>> > Fabio Maulo
>>>>
>>>>
>>>
>>>
>>> --
>>> Fabio Maulo
>>>
>>
>>
>>
>> --
>> Fabio Maulo
>>
>>
>>
>
> >
>


-- 
Fabio Maulo

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