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PODbUpdateConcurrencyException in Entity Framework Code First
 

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    <p>I'm having a issue with Entity Framework and Code First. I have an entity with a Timestamp property, and I add an new record to the database, call SaveChanges, and it's all ok. When I try to delete the record I've just added, I get the following message:</p> <blockquote> <p>Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.</p> </blockquote> <p>It seems to me that EF has no knowledge that this new record exists in database, despite the fact that it is there. Sometimes, even when I try to update an different record I get the same message, but if I try to delete an different one it works.</p> <p>Does anyone knows why this is happening?</p> <p>Thanks in advance, Diego</p> <p><strong>EDIT</strong> I've assembled some code to make it easier to understand my problem:</p> <p>I have two simple entities:</p> <pre><code>public class Entidade1 { [Key] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int ID { get; set; } public string Descricao { get; set; } [Timestamp] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public byte[] RecTS { get; set; } } public class Entidade2 { [Key] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int ID { get; set; } public string Descricao { get; set; } [Timestamp] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public byte[] RecTS { get; set; } public virtual Entidade1 Entidade1 { get; set; } } </code></pre> <p>The Context:</p> <pre><code>public class DB : DbContext { public DB() : base("DB") { this.Configuration.AutoDetectChangesEnabled = true; this.Configuration.LazyLoadingEnabled = true; this.Configuration.ProxyCreationEnabled = true; } public DbSet&lt;Entidade1&gt; Entidade1 { get; set; } public DbSet&lt;Entidade2&gt; Entidade2 { get; set; } } </code></pre> <p>And the code:</p> <p>var item = new Entidade1();</p> <pre><code> item.Descricao = "teste"; var db = new DB(); db.Set(typeof(Entidade1)).Add(item); db.SaveChanges(); var item2 = new Entidade2(); item2.Descricao = "teste 2"; item2.Entidade1 = item; db.Set(typeof (Entidade2)).Add(item2); db.SaveChanges(); var q = (from c in db.Entidade1 where c.Descricao == "teste" select c).FirstOrDefault(); db.Set(typeof(Entidade1)).Remove(q); db.SaveChanges(); var q2 = (from c in db.Entidade2 where c.Descricao == "teste 2" select c).FirstOrDefault(); db.Set(typeof (Entidade2)).Remove(q2); db.SaveChanges(); // Here I got the error </code></pre>
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    1. USDiego Modolo Ribeiro
    1. USDiego Modolo Ribeiro
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    1. COWhen the exceptions occurs and I call concurrencyException.Entries.Single().Reload(); it works, but I don't want an Exception to be thrown every time I save or delete a record.
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      1. USDiego Modolo Ribeiro
    2. COAre you using threads at all? (eg, ASP.Net)
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      1. USSLaks
    3. CONo, it's a single thread application. I don't know if it's important, but my Context is static.
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      1. USDiego Modolo Ribeiro
 

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