EF外鍵屬性不可爲空

Question

我有兩個完全相同的數據庫表，一個prod和一個dev。每當我部署到開發數據庫時，一切工作正常。並且prod數據庫允許將此錯誤與我試圖使用EF & MVC將數據寫回數據庫。

System.InvalidOperationException: 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. 
    at System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options) 
    at System.Data.Entity.Internal.InternalContext.SaveChanges() 

當然，我已經檢查這個http://blogs.msdn.com/b/dsimmons/archive/2010/01/31/deleting-foreign-key-relationships-in-ef4.aspx

好像沒有問題，我的EF代碼，純粹db表問題 無論如何，我可以找到更多的細節？

Answer 1

刪除外鍵關係在EF4 在這個問題上 http://blogs.msdn.com/b/dsimmons/archive/2010/01/31/deleting-foreign-key-relationships-in-ef4.aspx