Modeling Self-Reference Relationship Notes with Code First

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1.Has method:

A.HasRequired(a => a.B);

1. HasOptional: The former contains an instance of the latter or is null
2. HasRequired: The former (A) contains an instance of the latter (B) that is not null
3. HasMany: The former contains a collection of instances of the latter

Two.With method:

A.HasRequired(a => a.B);

1. WithOptional: The latter (B) can contain an instance of the former (A) or null
2. WithRequired: The latter contains a non-null instance of the former
3. WithMany: The latter contains a collection of instances of the former