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POUsing EF 4.1 Inserting a parent record and multiple child records as a single "Unit of Work"
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  1. POUsing EF 4.1 Inserting a parent record and multiple child records as a single "Unit of Work"
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    copied!<p>I am practicing with a code-first set of classes with a parent-child relationship between them. </p> <pre><code>public class Parent { public int Id ( get; set; } public string Name { get; set; } public List&lt;Child&gt; Children { get; set; } public Parent() { Children = new List&lt;Child&gt;(); } } public class Child() { public int Id ( get; set; } public string Name { get; set; } } public class MyContext : DbContext { public DbSet&lt;Parent&gt; Parents { get; set; } public DbSet&lt;Child&gt; Children { get; set; } } </code></pre> <p>In a simple console app I create a parent and create two child records and add them to the parent. If I then call the SaveChanges() only the first child is added to the children table.</p> <pre><code>var x = new MyContext(); var c1 = new Child { Name = "Alpha-Child" }; var c2 = new Child { Name = "Beta-Child" }; var p = new Parent {Name = "Alpha-Parent"}; p.Children.Add(c1); p.Children.Add(c2); x.Parents.Add(p); x.SaveChanges(); </code></pre> <p>Well that was not what I wanted, so I tried to maybe add then to both the parent object and the context object.</p> <pre><code>var x = new MyContext(); var c1 = new Child { Name = "Alpha-Child" }; var c2 = new Child { Name = "Beta-Child" }; var p = new Parent {Name = "Alpha-Parent"}; p.Children.Add(c1); p.Children.Add(c2); x.Children.Add(c1); x.Children.Add(c2); x.Parents.Add(p); x.SaveChanges(); </code></pre> <p>That got both the child records into the database, but only one of them (the first) was associated with the parent record.</p> <p>Last, but not least, I tried to do a call to SaveChanges() after each call to Parent.Add().</p> <pre><code>var x = new MyContext(); var c1 = new Child { Name = "Alpha-Child" }; var c2 = new Child { Name = "Beta-Child" }; var p = new Parent {Name = "Alpha-Parent"}; x.Parents.Add(p); p.Children.Add(c1); x.SaveChanges(); p.Children.Add(c2); x.SaveChanges(); </code></pre> <p>But, this breaks my idea of how the "Unit of Work" Pattern works. I "Should be able to call SaveChanges() once, and have all my changes take place, correct?</p> <p>So, what am I doing wrong?</p>
 

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