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PONhibernate 3.2 mapping by code. When we create a bag relation, what mean rm.OneToMany?
 

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  1. PONhibernate 3.2 mapping by code. When we create a bag relation, what mean rm.OneToMany?
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    <p>I use nhibernate 3.2 mapping by code and I've a strange behaviour.</p> <p>If I simplify my project, I have 2 tables :</p> <pre><code>[Serializable] public class Intervention { public Intervention() { ReponsePointVerification = new List&lt;ReponsePointVerification&gt;(); } #region Public Properties public virtual int Id { get; set; } public virtual IList&lt;ReponsePointVerification&gt; ReponsePointVerification { get; set; } } public class InterventionMap : ClassMapping&lt;Intervention&gt; { public InterventionMap() { Id&lt;int&gt;(x =&gt; x.Id, map =&gt; { map.Generator(NHibernate.Mapping.ByCode.Generators.Identity); }); Bag(x =&gt; x.ReponsePointVerification, map =&gt; { map.Key( k =&gt; k.Column( "IdIntervention" ) ); }); } } </code></pre> <p>and </p> <pre><code>[Serializable] public class ReponsePointVerification { #region Public Properties public virtual int Id { get; set; } public virtual Intervention Intervention { get; set; } } public class ReponsePointVerificationMap : ClassMapping&lt;ReponsePointVerification&gt; { public ReponsePointVerificationMap() { Id&lt;int&gt;(x =&gt; x.Id, map =&gt; { map.Generator(NHibernate.Mapping.ByCode.Generators.Identity); }); ManyToOne&lt;Intervention&gt;(x =&gt; x.Intervention, map =&gt; map.Column("IdIntervention")); } } </code></pre> <p>which represents two tables Intervention and ReponsePointVerification which has a foreign key (IdIntervention) which is linked to Intervention.</p> <p>When I call :</p> <pre><code> return (from interv in Session.Query&lt;Intervention&gt;() .Fetch(rep =&gt; rep.ReponsePointVerification) select interv).ToList(); </code></pre> <p>or even when I don't fetch the information. I has this error :</p> <pre><code>Could not cast the value in field id0_ of type Int32 to the Type SerializableType. Please check to make sure that the mapping is correct and that your DataProvider supports this Data Type. </code></pre> <p>The sql query looks to be ok.</p> <p>I found that post <a href="http://groups.google.com/group/nhusers/browse_thread/thread/ef137c3e5b66acdc" rel="nofollow">http://groups.google.com/group/nhusers/browse_thread/thread/ef137c3e5b66acdc</a></p> <p>And I modify the InterventionMap class according to that post it will work :</p> <pre><code>public class InterventionMap : ClassMapping&lt;Intervention&gt; { public InterventionMap() { Id&lt;int&gt;(x =&gt; x.Id, map =&gt; { map.Generator(NHibernate.Mapping.ByCode.Generators.Identity); }); Bag(x =&gt; x.ReponsePointVerification, map =&gt; { map.Key( k =&gt; k.Column( "IdIntervention" ) ); }, rm =&gt; rm.OneToMany()); } } </code></pre> <p>The only difference is the add of ", rm => rm.OneToMany()"</p> <p>Trust me I'm very happy it worked but I really don't understand that line can someone explain me the meaning ?</p> <p>Regards</p> <p><strong>Edit</strong></p> <p>I made a WriteAllXmlMapping and the 2 codes are :</p> <p><strong>version without rm => rm.OneToMany() (which doesn't work)</strong></p> <pre><code>&lt;bag name="ReponsePointVerification"&gt; &lt;key column="IdIntervention" /&gt; &lt;element type="Hyma.BusinessObjets.ReponsePointVerification" /&gt; &lt;/bag&gt; </code></pre> <p><strong>version with rm => rm.OneToMany() (which work)</strong></p> <pre><code>&lt;bag name="ReponsePointVerification"&gt; &lt;key column="IdIntervention" /&gt; &lt;one-to-many class="ReponsePointVerification" /&gt; &lt;/bag&gt; </code></pre>
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    1. USP. Sohm
    1. USP. Sohm
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      1. PONhibernate 3.2 mapping by code. When we create a bag relation, what mean rm.OneToMany?
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    1. COThe third parameter defines the relation that mapped collection takes part in. Generally there should be no difference as `OneToMany` is the default, AFAIK. Try generating the XML mappings (`WriteAllXmlMapping` method) to see if there is any difference.
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      1. PONhibernate 3.2 mapping by code. When we create a bag relation, what mean rm.OneToMany?
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    2. COthank you for your tip, it is simplier with xml
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      1. USP. Sohm
 

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