public DbSet <TEntity> SetOf <TEntity>() where TEntity : Entity { if (Flights is IEnumerable <TEntity> ) { Tickets.Load(); return(Flights as DbSet <TEntity>); } else if (Depatures is IEnumerable <TEntity> ) { Tickets.Load(); Flights.Load(); Pilots.Load(); Stewardesses.Load(); Crew.Load(); Types.Load(); Planes.Load(); return(Depatures as DbSet <TEntity>); } else if (Crew is IEnumerable <TEntity> ) { Pilots.Load(); Stewardesses.Load(); return(Crew as DbSet <TEntity>); } else if (Stewardesses is IEnumerable <TEntity> ) { return(Stewardesses as DbSet <TEntity>); } else if (Pilots is IEnumerable <TEntity> ) { return(Pilots as DbSet <TEntity>); } else if (Planes is IEnumerable <TEntity> ) { Types.Load(); return(Planes as DbSet <TEntity>); } else if (Types is IEnumerable <TEntity> ) { return(Types as DbSet <TEntity>); } else { Flights.Load(); return(Tickets as DbSet <TEntity>); } }