EntityType 'ApplicantPosition' has no key defined

Question

When running my first asp.net mvc application I got this error I thought that entity framework automatically would create the keys of column names that end with Id? isnt it

Answer 1

In your case, EF naming convention first looks for an ID (case-insensitive) column. If nothing, looks for ApplicantImageId and when it founds nothing, it raises that error.

So, you should add the [Key] attribute on your ID:

public class ApplicantImage
{
    [Key]
    public int ApplicantId { get; private set; }
    public byte[] Image { get; set; }
}

and if ApplicantId column is identity in your database, you should add another attribute too:

public class ApplicantImage
{
    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int ApplicantId { get; private set; }
    public byte[] Image { get; set; }
}