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POEntity Framework: Shouldn't attaching the following entity throw an exception?
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  1. POEntity Framework: Shouldn't attaching the following entity throw an exception?
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    copied!<p>As far as I can tell, <code>EntityCollection.Attach</code> and <code>EntityReference.Attach</code> can only create relationships that already exists in the database. In other words, if <code>Address.EmployeeID == Employee.EmployeeID</code>, then the following code will work:</p> <pre><code> Employee employee = context.Employees.First(); Address address = context.Addresses.First(); employee.Addresses.Attach(address); </code></pre> <p>But if <code>Address.EmployeeID != Employee.EmployeeID</code>, then the code will throw an exception:</p> <pre><code> Employee employee = context.Employees.First(); Address address = context.Addresses.First(); employee.Addresses.Attach(address); // System.InvalidOperationException: A // referential integrity constraint // violation occurred </code></pre> <p>But according to a code example taken from the following <a href="https://stackoverflow.com/questions/3920111/entity-framework-4-addobject-vs-attach">thread</a>, <code>EntityCollection.Attach</code> and <code>EntityReference.Attach</code> can also be used to create a relationship that doesn't exist in a DB:</p> <pre><code>var existingPerson = ctx.Persons.SingleOrDefault(p =&gt; p.Name = "Joe Bloggs" }; var myAddress = ctx.Addresses.First(a =&gt; a.PersonID != existingPerson.PersonID); existingPerson.Addresses.Attach(myAddress); // OR: myAddress.PersonReference.Attach(existingPerson) ctx.SaveChanges(); </code></pre> <p>So am I correct in assuming that <code>EntityCollection.Attach</code> and <code>EntityReference.Attach</code> can only create relationships that already exists in the database, and as such code example taken from the other thread should throw an exception?</p> <p>Thank you </p>
 

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