ManyToOne attributes as inverse to List attribute

gene · **Posted:** Sun Dec 18, 2005 5:37 pm

I have a class that holds a list of other classes, as follows:

Code:

// UniqueObject defines the ID attribute.
[NHibernate.Mapping.Attributes.Class(Table="AnalysisData")]
public class AnalysisData : UniqueObject
{
   #region Properties
   private IList analysisResultsList = new ArrayList();
   [NHibernate.Mapping.Attributes.List(Cascade=CascadeStyle.AllDeleteOrphan)]
   [NHibernate.Mapping.Attributes.Key(1, Column="AnalysisDataID")]
   [NHibernate.Mapping.Attributes.Index(2, Column="AnalysisDataSequence")]
   [NHibernate.Mapping.Attributes.OneToMany(3, ClassType=typeof(AnalysisResult))]
   public IList AnalysisResultsList
   {
      get { return this.analysisResultsList; }
      set { this.analysisResultsList = value; }
   }
}

and

Code:

[NHibernate.Mapping.Attributes.Class(Table="AnalysisResults")]
public class AnalysisResult: UniqueObject
{
   #region Properties
   private string description;
   /// <summary> Textual description</summary>
   [NHibernate.Mapping.Attributes.Property]
   public string Description
   {
      get { return this.description; }
      set { this.description = value; }
   }
   // other properties deleted for clarity...
   #endregion Properties
}

I understand that to get the list objects to be retrieved, I need a ManyToOne element in the AnalysisResult class, but I don't understand how I attach it if my DOM doesn't have a parent property.

Ideas?

Thanks!

Gene

KPixel · **Posted:** Mon Dec 19, 2005 7:50 am

I am not sure to understand your problem... You need a relationship in the mapping whenever you want to be able to browse it that way.
So you need a ManyToOne if you want to be able to go from the Many side to the One side.

I move this topic as it has nothing to do with a Contribution/Tool.

gene · **Posted:** Mon Dec 19, 2005 12:58 pm

KPixel wrote:

I am not sure to understand your problem... You need a relationship in the mapping whenever you want to be able to browse it that way.
So you need a ManyToOne if you want to be able to go from the Many side to the One side.

I move this topic as it has nothing to do with a Contribution/Tool.

I am sorry I was not clear. I am posting to this list because I believe the question is related to NHibernate.Mapping.Attributes. If this is the wrong place for that discussion, I apologize for my misunderstanding.

I don't want to have a child->parent link, but I want to have a NHibernate.Mapping.Attributes.List in the parent that contains a bunch of children. When I just code the list, however, the childrens' index fields are not saved when they are written into the database. My interpretation of the documentation was that I needed a ManyToOne attribute on the child to represent the index field (that is, a reference to the parent instance). My question is how I specify that attribute when my DOM doesn't call for a child->parent link. (And furthermore, Sergey pointed out that it's not possible to have bi-directional links with Lists.)

Thanks for your help,

Gene

sergey · **Posted:** Fri Dec 23, 2005 5:58 am

NHibernate assumes that the collection belongs to the parent and will set the child indices when the parent is saved.