使用组合键将单向1映射为零或一

Question

There are two classes, inheriting from a single base class (I believe this should be irrelevant), corresponding to two tables in an sqlite database.
Both of these classes hold values for a license key, and values for when the entry was created and last updated.

Also of note is that a single license may have any number of events associated with it, but only one event can be defined to auto start per license. Also, the connection is unidirectional; the autostart object will always refer to an event, but not all events have an autostart object referring to them, and all events are unaware whether they are an autostart event or not.

The class definitions:

public abstract class EntityBase : IModel, ITimestampedEntity
{
    public virtual string LicenseKey { get; set; }
    public virtual DateTime? CreatedAt { get; set; }
    public virtual DateTime? UpdatedAt { get; set; }
}

public class Event : EntityBase, IEvent
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime EndDate { get; set; }
}

public class AutoStart : EntityBase
{
    public Event Event { get; set; }
}

I'll provide the sql for the two tables in the sqlite database:

CREATE TABLE `event` (
  `id`  INTEGER NOT NULL,
  `name`    TEXT NOT NULL,
  `start_date`  TEXT,
  `end_date`    TEXT,
  `license_key` TEXT,
  `created_at`  TEXT,
  `updated_at`  TEXT,
  PRIMARY KEY(`id`,`license_key`)
);

CREATE TABLE `autostart_event` (
  `license_key` TEXT NOT NULL,
  `event_id`    INTEGER NOT NULL,
  `created_at`  TEXT,
  `updated_at`  TEXT,
  PRIMARY KEY(`license_key`),
  FOREIGN KEY(`license_key`) REFERENCES `event`(`license_key`) ON UPDATE CASCADE,
  FOREIGN KEY(`event_id`) REFERENCES `event`(`id`) ON UPDATE CASCADE
);

Note that we use a more sql conform naming schedule than EF6 would use by itself. For this reason the column names are defined in the mapping.

The tables are mapped using the Entity Framework Fluent API. The mapping defined in the context is as follows:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    // Fluent API event table mapping properties
    var eventMapping = modelBuilder.Entity<Event>().ToTable("event");
    eventMapping.HasKey(@event => new { @event.Id, @event.LicenseKey }).Property(@event => @event.Id).HasColumnName("id").HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);
    eventMapping.Property(@event => @event.Name).HasColumnName("name").IsRequired();
    eventMapping.Property(@event => @event.StartDate).HasColumnName("start_date");
    eventMapping.Property(@event => @event.EndDate).HasColumnName("end_date");
    eventMapping.Property(@event => @event.LicenseKey).HasColumnName("license_key");
    eventMapping.Property(@event => @event.CreatedAt).HasColumnName("created_at");
    eventMapping.Property(@event => @event.UpdatedAt).HasColumnName("updated_at");

    // Fluent API event_autostart table mapping properties
    var autoStartMapping = modelBuilder.Entity<AutoStart>().ToTable("autostart_event");
    autoStartMapping.HasKey(autoStart => autoStart.LicenseKey).Property(autoStart => autoStart.LicenseKey).HasColumnName("license_key");
    autoStartMapping.HasRequired(autoStart => autoStart.Event).WithRequiredPrincipal().Map(map => map.MapKey("event_id"));
    autoStartMapping.Property(autoStart => autoStart.CreatedAt).HasColumnName("created_at");
    autoStartMapping.Property(autoStart => autoStart.UpdatedAt).HasColumnName("updated_at");
}

As shown here the event table has a composite primary key index, composing both id and license_key.
An autostart object only has a single primary key: license_key (since only one autostart event may be defined per license).

I'm able to save and retrieve events from the database, but on saving an autostart object an exception is thrown stating:

SQL logic error foreign key mismatch - "autostart_event" referencing "event"

I believe this is due to the composite key and the non-default column names (after all, the column name is event_id, not event), however, I've been unable to find how to map the column names correctly for a one to one or zero-one relation.
The documentation refers to the HasForeignKey() method, but this is only available for DependentNavigationPropertyConfiguration objects, which are returned by a RequiredNavigationPropertyConfiguration . WithMany() call. But since there is no many relation here...