如何发布一对多的关系？

Question

ASP.NET和编程方面的新手。我有两个模型，两个API控制器，两个存储库。如何在将数据附加到第一个模型时将数据发布到第二个模型（我是通过ID猜测的。）我是否可能需要View模型？还阅读一些关于工作单元的内容。也许两者都没有必要？下面是一些代码。谢谢！

Record.cs

        public static void buildTree(String treeFile){
        //temp string array to hold the input as 3 seperate Strings, seperated by ;
        String[] temp= new String[3];
        int i=0;

        //will split the string into its 3 parts
        for (String newTemp: treeFile.split(";")) {
            temp[i]=newTemp;
            i++;
           }

        //can hold up to 100 char, each describing a path
        char[] pathArray= new char[100];
        int pathCursor=0;

        i=0;
        //once again split the first part of the string, which holds the path, into an array of chars,
        //parse each String into a char and then set equal to in array in array
        for(String newTemp: temp[0].split("-")){
            char c=newTemp.charAt(0);
            pathArray[i]=c;
            i++;
            pathCursor++;
        }

        for(int j=0; j<3;j++){
            System.out.println(temp[j]);
        }

        for(int j=0; j<pathCursor;j++){
            System.out.println(pathArray[j]);
        }
    }

}

Cars.cs

namespace Train.Models {
public class Record {
    public int Id { get; set; }
    public int Quantity { get; set; }
    public DateTime DateCreated { get; set; }
    public bool IsActive { get; set; }
    public string UserId { get; set; }
    public virtual ICollection<Cars> Cars { get; set; }
}

}

记录存储库

namespace Train.Models {
public class Cars {
    public int Id { get; set; }
    public string EmptyOrLoaded { get; set; }
    public string CarType { get; set; }
    //Hopper, flatbed, tank, gondola, etc.
    public string ShippedBy { get; set; }
    //UP(Union Pacific) or BNSF
    public string RailcarNumber { get; set; }
    //public virtual ApplicationUser ApplicationUser { get; set; }
    public string UserId { get; set; }
    public string RecordId { get; set; }
    public virtual Record Record { get; set; }

}

EFRepository（汽车）

       public void SaveRecord(Record recordToSave) {

        if (recordToSave.Id == 0) {
            recordToSave.DateCreated = DateTime.Now;
            _db.Record.Add(recordToSave);
            _db.SaveChanges();

        } else {
            var original = this._db.Record.Find(recordToSave.Id);
            original.Quantity = recordToSave.Quantity;
            original.IsActive = true;

            _db.SaveChanges();
        }
    }