如何在实体框架中正确地实现多到一个结构？

Question

我知道这是一个古老的问题，但我只是无法使它发挥作用，我会喜欢一个人类的解释！

我在我的数据库中有四个表，我只想调用一个api来获取数据--这些表代表不同的实体、书籍、文章、案例和法规，我想要一个叫做书目的模型，它把所有这些都整合在一起。

我尝试了以下方法，但是在向表中添加数据并调用此表的控制器后，我得到了一个200 ok的数据。

My models:

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Web;

namespace PhDResourceManager.Models
{
    public class Journal
    {
        public Journal() { }
        [Key]
        public int ID { get; set; }
        public string Title { get; set; }
        public string Author { get; set; }
        public string PublicationYear { get; set; }
        public string PublicationName { get; set; }
        public string PageNumber { get; set; }
        public virtual Bibliography Bibliography { get; set; }
    }

    public class Book
    {
        public Book() { }
        [Key]
        public int ID { get; set; }
        public string Author { get; set; }
        public string Title { get; set; }
        public string Edition { get; set; }
        public string PublicationYear { get; set; }
        public string PublisherName { get; set; }
        public string PageNumber { get; set; }
        public virtual Bibliography Bibliography { get; set; }
    }

    public class Case
    {
        public Case() { }
        [Key]
        public int ID { get; set; }
        public string Parties { get; set; }
        public string NeutralCitation { get; set; }
        public string LawReportsCitation { get; set; }
        public virtual Bibliography Bibliography { get; set; }
    }

    public class Statute
    {
        public Statute() { }
        [Key]
        public int ID { get; set; }
        public string Title { get; set; }
        public string Section { get; set; }
        public string Year { get; set; }
        public virtual Bibliography Bibliography { get; set; }
    }

    public class Bibliography
    {
        public Bibliography()
        {
            MyJournals = new List<Journal>();
            MyCases = new List<Case>();
            MyBooks = new List<Book>();
            MyStatutes = new List<Statute>();
        }
        [Key]
        public int ID { get; set; }
        public virtual ICollection<Journal> MyJournals { get; set; }
        public virtual ICollection<Case> MyCases { get; set; }
        public virtual ICollection<Book> MyBooks { get; set; }
        public virtual ICollection<Statute> MyStatutes { get; set; }
    }
}

我的控制器：

namespace PhDResourceManager.Controllers
{
    public class BibliographyController : ApiController
    {
        private PhDResourceManagerContext db = new PhDResourceManagerContext();

        // GET: api/Bibliography
        public IQueryable<Bibliography> GetBibliographies()
        {
            return db.Bibliographies;
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                db.Dispose();
            }
            base.Dispose(disposing);
        }

        private bool BibliographyExists(int id)
        {
            return db.Bibliographies.Count(e => e.ID == id) > 0;
        }
    }
}

Answer 1

将方法更改为：

 public Bibliography GetBibliographies()
        {
                Bibliography bibliography = new Bibliography();
                bibliography.MyJournals = db.Journal.ToList();
                bibliography.MyCases = db.Cases.ToList();
                bibliography.MyBooks = db.Books.ToList();
                bibliography.MyStatutes = db.Statutes.ToList();
                return bibliography;
        }

Answer 2

您应该像其他人建议的那样使用.Include()。如果您的表具有适当的关系，它们将与您的GetBibliographies api一起下降。

https://msdn.microsoft.com/en-us/data/jj574232.aspx