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PONHibernate Many To Many Relationship - Issue when deleting a part of the relationship
 

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  1. PONHibernate Many To Many Relationship - Issue when deleting a part of the relationship
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    <p>I have a many to many relationship between a Team and an Employee entity.</p> <p>I mapped them as following:</p> <pre><code>public class EmployeeMap : ClassMap&lt;Employee&gt; { public EmployeeMap() { // identifier mapping Id(p =&gt; p.Id).Column("EmployeeID"); // column mapping Map(p =&gt; p.EMail); Map(p =&gt; p.LastName); Map(p =&gt; p.FirstName); // relationship mapping HasManyToMany(m =&gt; m.Teams).Table("EmployeeTeam") .Inverse() .Cascade.All() .AsSet() .LazyLoad() .ParentKeyColumn("EmployeeID") .ChildKeyColumn("TeamID"); HasMany(p =&gt; p.LoanedItems).Cascade.SaveUpdate().KeyColumn("EmployeeId"); } } public class TeamMap : ClassMap&lt;Team&gt; { public TeamMap() { // identity mapping Id(p =&gt; p.Id).Column("TeamID"); // column mapping Map(p =&gt; p.Name); // relationship mapping HasManyToMany(m =&gt; m.Employees) .Table("EmployeeTeam") .LazyLoad() .Cascade.All() .AsSet() .ParentKeyColumn("TeamID") .ChildKeyColumn("EmployeeID"); } } </code></pre> <p>Then I created 3 Teams and 2 Employees:</p> <pre><code>TeamID EmployeeID 1 1 1 2 2 2 3 1 </code></pre> <p>The Employee1 has also 2 LoanedItems(Books, Magazines). Employee2 has no LoanedItems.</p> <p>Now I want to delete Employee1, who is in Team1 and Team3. In Team 1 is also Employee2. So when I delete Employee1, I assume that Employee1 is deleted and also Team3, because I also assume that an Team can only exist when it has an Employe and vice versa. So Team1 may not be deleted, because it has Employee2 and can still exists. </p> <p>I used the following code lines with a new Session: </p> <pre><code>var loadedEmployee = session.Get&lt;Employee&gt;(1); session.Delete(loadedEmployee); transaction.Commit(); </code></pre> <p>But what happens? -> <strong>NHibernate deletes all Teams and all Employees</strong>! -> NHibernate updated my LoanedItem table correctly by setting the FK EmployeeID to NULL.</p> <p>What is wrong there?</p>
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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

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