Question

我试图为一些具有一对多关系的数据库表种子。使用代码第一种方法与实体框架。不知何故，外键在数据库表活动中保持为空，列为UserId。

为什么这不起作用？

        context.Users.AddOrUpdate(
          u => u.FirstName,
           new User { Id = 1, FirstName = "Trees", Preposition = "de", LastName = "Vries", EmailAddress = "trees@test.com", PhoneNumber = 0684637485, Password = "test123", RoleId = 1 }
         );
        context.SaveChanges();


        context.Activities.AddOrUpdate(
            a => a.Name,
            new Activity
            {
                Name = "Metselen van de binnenplaats",
                Comment = "Voorbeeld commentaar regel 1.",
                Start = DateTime.Now,
                End = DateTime.Now.AddHours(5),
            },//etc.
            );
        context.SaveChanges();

        var randomActivities = (from s in context.Activities select s).OrderBy(x => Guid.NewGuid()).Take(6).ToList();

        context.Users.AddOrUpdate(
          u => u.Id,
           new User { Id = 1, Activities = randomActivities }
         );
        context.SaveChanges();

编辑：解决方案

经过几个小时的代码摔跤后，我终于设法让它全部正常工作（无需在模型类中添加外键）。

我将分享代码和一些发现，以便其他人可以从中受益。

要记住一些事情。

直接编码到上下文！

这不起作用：

   List<Activity> randomActivities = (from s in context.Activities select s).OrderBy(x => Guid.NewGuid()).Take(2).ToList(); //Does not work

使用：

List<Activity> randomActivities = context.Activities.OrderBy(x => Guid.NewGuid()).Take(2).ToList();

当您需要链接已经需要在表中的对象时，只调用SaveChanges（）。

context.SaveChanges();

最后，你可以创建与其他表有关系的数据，只需在其中添加一个新的List（详见下面的代码）。

种子方法现在看起来像这样：

 var users = new List<User>
        {
            new User
            {
                FirstName = "Trees", 
                Preposition = "de", 
                LastName = "Vries", 
                EmailAddress = "trees@test.com", 
                PhoneNumber = 0684637485, 
                Password = "test123",
                Activities =
                new List<Activity> { // <-- Like this!
                    new Activity { Name = "Boren muren in de grote hal 1", Start = DateTime.Now, End = DateTime.Now.AddHours(5) },
                    new Activity { Name = "Vloer schuren 1", Start = DateTime.Now, End = DateTime.Now.AddHours(1) },
                    new Activity { Name = "Boren muren in de grote hal 2", Start = DateTime.Now, End = DateTime.Now.AddHours(5) },
                    new Activity { Name = "Vloer schuren 2", Start = DateTime.Now, End = DateTime.Now.AddHours(1) }
                },
                Messages =
                new List<Message>
                {
                    new Message { Subject = "Test onderwerp van bericht 1", Body = "Tekst van het bericht 1", AuthorId = 3 },
                    new Message { Subject = "Test onderwerp van bericht 2", Body = "Tekst van het bericht 2", AuthorId = 3 },
                    new Message { Subject = "Test onderwerp van bericht 3", Body = "Tekst van het bericht 3", AuthorId = 3 }
                }
            },
            new User { FirstName = "Jaap", LastName = "Winter", EmailAddress = "jaap@test.com", PhoneNumber = 0628305643, Password = "test123"  },
            new User { FirstName = "Klaas", LastName = "Janssen", EmailAddress = "klaas@test.com", PhoneNumber = 0639453321, Password = "test123" }
        };
        users.ForEach(s => context.Users.AddOrUpdate(r => r.FirstName, s));
        context.SaveChanges();

        List<Activity> randomActivities = context.Activities.OrderBy(x => Guid.NewGuid()).Take(2).ToList();
        var projects = new List<Project>
        {
            new Project { Name = "Test project", Description = "Omschrijving van test project 1.", Start = DateTime.Now, End = DateTime.Now.AddDays(10), User = context.Users.Single(s => s.FirstName == "Trees"), Activities = randomActivities }
        };
        projects.ForEach(s => context.Projects.AddOrUpdate(r => r.Name, s));

活动模型类：

    public class Activity
{
    public int Id { get; set; }

    public string Name { get; set; }
    public DateTime Start { get; set; }
    public DateTime End { get; set; }

    public Skill Skill { get; set; }
    public string Comment { get; set; }
}

用户模型类：

    public int Id { get; set; }

    public string FirstName { get; set; }
    public string Preposition { get; set; }
    public string LastName { get; set; }
    public string EmailAddress { get; set; }
    public int PhoneNumber { get; set; }
    public string Password { get; set; }
    public bool Active { get; set; }

    public Role Role { get; set; }

    public ICollection<Skill> Skills { get; set; }
    public ICollection<Message> Messages { get; set; }
    public ICollection<Activity> Activities { get; set; }
  }

种子表与一对多关系EF代码优先

0 个答案: