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<h1>Cascading Deletion</h1>
<p>By default db4o only deletes objects which are passed to the delete-method and doesn't delete referenced objects. You can easily change that. Configure the cascading deletion behavior in the configuration for <a href="../../configuration/objectclass/cascade_on_delete.htm">certain classes</a> or <a href="../../configuration/objectfield_configuration.htm">certain fields</a>. </p>
<p>For example we mark that the object in the 'pilot'-field is also deleted:</p>
<div class="codesnippet" MadCap:conditions="Primary.c#">
<pre class="prettyprint" xml:space="preserve">IEmbeddedConfiguration config = Db4oEmbedded.NewConfiguration();
config.Common.ObjectClass(typeof (Car)).ObjectField("pilot").CascadeOnDelete(true);
using (IObjectContainer container = Db4oEmbedded.OpenFile(config, DatabaseFile))
{</pre>
<div class="codesnippet-meta">DeletionExamples.cs: Mark field for cascading deletion
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<pre class="prettyprint lang-vb" MadCap:conditions="Primary.Online" xml:space="preserve">Dim config As IEmbeddedConfiguration = Db4oEmbedded.NewConfiguration()
config.Common.ObjectClass(GetType(Car)).ObjectField("pilot").CascadeOnDelete(True)
Using container As IObjectContainer = Db4oEmbedded.OpenFile(config, DatabaseFile)</pre>
<div class="codesnippet-meta">DeletionExamples.vb: Mark field for cascading deletion
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<p>When we now delete the car, the pilot of that car is also deleted.</p>
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<pre class="prettyprint" xml:space="preserve">Car car = FindCar(container);
container.Delete(car);
// Now the pilot is also gone
AssertEquals(0, AllPilots(container).Count);</pre>
<div class="codesnippet-meta">DeletionExamples.cs: Cascade deletion
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<div class="codesnippet" MadCap:conditions="Primary.VB.NET">
<pre class="prettyprint lang-vb" MadCap:conditions="Primary.Online" xml:space="preserve">Dim car As Car = FindCar(container)
container.Delete(car)
' Now the pilot is also gone
AssertEquals(0, AllPilots(container).Count)</pre>
<div class="codesnippet-meta">DeletionExamples.vb: Cascade deletion
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