Question

I keep getting this error :

Cannot insert the value NULL into column ‘Id’, table
‘database.dbo.Employees’; column does not allow nulls. INSERT
fails.\r\nThe statement has been terminated.

But the object has this property set with Guid.NewGuid()

I use Entity Framework 4.1 and .net framework 4.0.

The column is primary key and not null. I’m not using Code First approach.

Edit : it seems that the Run Custom tool won’t update the file if I edit manually the file edmx.

Answer 1

This can happen if you have marked the key property as an autogenerated identity in your model with Fluent API or data annotations…

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid Id { get; set; }

… (which has the effect that EF won’t send the Id value to the database because it expects that the key is generated there) but in your database table you didn’t specify that the default value for the Id column is newid() so that the database doesn’t generate a new key.

I you want to send the Guid value manually from the client to the database remove the DatabaseGeneratedOption.Identity specification from your model.