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POEntity Framework 5 - Deleting Child Records
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  1. POEntity Framework 5 - Deleting Child Records
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    copied!<p>VS 2012 (11.0.60315.01 Update 2), C# 5, Entity Framework 5.0.0.0 (Runtime v4.0.30319) </p> <p>I know similar questions have been posted in the past, but there does not seem to be an answer. I think I understand the error, but I'm more interested in finding the 'desired' solution. <strong>All I want to do is delete a record from the Child table.</strong> Can anyone help? </p> <p>This is a <strong>full</strong> and <strong>simple</strong> example. The <strong>SaveChanges()</strong> throws the following exception:</p> <p>"The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted."</p> <p>The code looks like this:</p> <pre><code>using System.Linq; namespace EFDeleteTest { class Program { static void Main(string[] args) { using (EFTestEntities context = new EFTestEntities()) { var parent = context.Parents.Single(p =&gt; p.Id == 1); var child = parent.Children.Single(c =&gt; c.Id == 1); parent.Children.Remove(child); context.SaveChanges(); // Throws the above Exception } } } } </code></pre> <p>The Database looks like this:</p> <pre><code>Parent Id (PK, int, not null) IDENTITY Name (nvarchar(50), null) Child Id (PK, int, not null) IDENTITY ParentId (FK, int, not null) -- Foreign Key to the Parent Table (Id column)) Name (nvarchar(50), null) </code></pre> <p>There is one record in the Parent table (Id = 1) and there are 2 records in the Child table (Id's 1 and 2). Both of the Child records have a ParentId = 1.</p>
 

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