InvalidOperationException: The entity type 'object' requires a key to be defined - entity-framework

Question

Entity-framework 7.
[Table("Settings")]
public class Setting
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public object DefaultValue { get; set; }
public string Classification { get; set; }
public FacilitySettingOverride FacilitySettingOverride { get; set; }
}
[Table("FacilitySettingOverride")]
public class FacilitySettingOverride
{
[Key]
[ForeignKey("FacilityId")]
public int FacilityId { get; set; }
public object Value { get; set; }
[ForeignKey("SettingId")]
public int SettingId { get; set; }
public virtual ICollection<Setting> Settings { get; set; }
}
[Table("Facilities")]
public class Facility
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<FacilitySettingOverride> FacilitySettingOverrides { get; set; }
}
When run the code
private IEnumerable<FacilitySettingOverride> GetFacilityBandwidthSettings
{
get
{
List<FacilitySettingOverride> settingList;
using (SettingDbContext context = new SettingDbContext())
{
settingList = context.FacilitySettingOverride.ToList();
}
return settingList;
}
}
Then get the exception:
InvalidOperationException: The entity type 'object' requires a key to be defined.
The context is:
public class SettingDbContext : DbContext
{
public DbSet<Setting> Settings { get; set; }
public DbSet<FacilitySettingOverride> FacilitySettingOverride { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer("Data Source=13.53.63.74;Initial Catalog=AAAAA;User ID=sa;password=password);
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
}
}
However if I change the object to string for Value or DefaultValue in POCO then no exception. But the type in the database is sql_variant. I have to use the type object.

Answer 1

It seems that Data annotations are not yet supported so you will need to use the Fluent API for configuration.
See: https://github.com/aspnet/EntityFramework/issues/1913#issuecomment-86662854