实体框架 6 代码优先:如何为具有“循环”关系的数据和存储生成的列设定种子

我是 EF Code First 的新手，我正在尝试使用代码优先迁移为我的数据库提供一些数据种子。到目前为止，我已经设法解决了几个错误，但现在我被困住了，无法找到答案。从我的代码更新数据库时有两个问题。

我有几个对象，它们具有各种多对多和一对一的关系，有些最终会创建一个圆。当我尝试为数据库播种时，我不确定这是否是第二个问题的原因。

1. 我遇到的第一个错误是：A dependent property in a ReferentialConstraint is mapped to a store-generated column. Column: 'LicenseId'.

有没有办法将数据库生成的 id 用作外键？只是我创建/插入对象的顺序吗？(请参阅下面的种子设定代码(

如果我在许可证中不使用[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]，则会收到一个错误，提示无法隐式插入不是由数据库生成的 id。

public class License : Entity
{
    [Key, ForeignKey("Customer")]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int LicenseId { get; set; }
    [Required(ErrorMessage = "Date Created name is required")]
    public DateTime DateCreated { get; set; }
    public virtual ICollection<ProductLicense> ProductLicenses { get; set; } // one License has many ProductLicenses
    public virtual Customer Customer { get; set; } // one Customer has one License
}
public class Customer : Entity
{
    [Key]
    public int CustomerId { get; set;}
    [Required(ErrorMessage = "Username is required")]
    [Column(TypeName = "nvarchar")]
    [MaxLength(500)]
    public string Name { get; set; }
    public virtual ICollection<User> Users { get; set; } // one Customer has many users
    public virtual License License { get; set; } // one Customer has one License
    //public virtual ICollection<License> License { get; set; } // one Customer has many Licenses
}

2. 如果我将许可证客户更改为多对多关系(我不想要(，则会出现以下错误：Cannot insert duplicate key row in object 'dbo.Users' with unique index 'IX_Username'.

这些是我的所有关系：

Customer -many-> User -many-> Role -many-> Permission -one- ProductLicense <-many- License -one- Customer

这是我在protected override void Seed(DAL.Models.Context context)中使用的代码，在代码中创建对象，然后使用AddOrUpdate：

// Default Customers - create
var customers = new[]{
    new Customer { Name = "cust_a" },
    new Customer { Name = "cust_b" },
    new Customer { Name = "cust_c" }
};
// Default Licenses - create
var licenses = new[]{
    new License { DateCreated = DateTime.Now.AddDays(-3), Customer = customers[0] },
    new License { DateCreated = DateTime.Now.AddDays(-2), Customer = customers[1] },
    new License { DateCreated = DateTime.Now.AddDays(-1), Customer = customers[2] }
};
// Default ProductLicenses - create, and add default licenses
var productLicenses = new[]{
    new ProductLicense { LicenceType = LicenseType.Annual, StartDate = DateTime.Now, License = licenses[0] },
    new ProductLicense { LicenceType = LicenseType.Monthly, StartDate = DateTime.Now, License = licenses[1] },
    new ProductLicense { LicenceType = LicenseType.PAYG, StartDate = DateTime.Now, License = licenses[2] }
    };
// Default Permissions - create, and add default product licenses
var permissions = new[]{
    new Permission { Name = "Super_a", ProductLicense = productLicenses[0] },
    new Permission { Name = "Access_b", ProductLicense = productLicenses[1] },
    new Permission { Name = "Access_c", ProductLicense = productLicenses[2] }
};
// Default Roles - create, and add default permissions
var roles = new[]{
    new Role { Name = "Super_a", Permissions = permissions.Where(x => x.Name.Contains("_a")).ToList() },
    new Role { Name = "User_b", Permissions = permissions.Where(x => x.Name.Contains("_b")).ToList() },
    new Role { Name = "User_c", Permissions = permissions.Where(x => x.Name.Contains("_c")).ToList() }
};
// Default Users - create, and add default roles
var users = new[]{
    new User { Username = "user@_a.com", Password = GenerateDefaultPasswordHash(), Salt = _defaultSalt, Roles = roles.Where(x => x.Name.Contains("_a")).ToList() },
    new User { Username = "user@_b.co.uk", Password = GenerateDefaultPasswordHash(), Salt = _defaultSalt, Roles = roles.Where(x => x.Name.Contains("_b")).ToList() },
    new User { Username = "user@_c.com", Password = GenerateDefaultPasswordHash(), Salt = _defaultSalt, Roles = roles.Where(x => x.Name.Contains("_c")).ToList() }
        };
// Default Customers - insert, with default users
foreach (var c in customers)
{
    c.Users = users.Where(x => x.Username.Contains(c.Name.ToLower())).ToList();
    context.Customers.AddOrUpdate(c);
}

我还尝试将//Default Customers - create后的第一部分更改为

// Default Customers - create and insert
context.Customers.AddOrUpdate(
    u => u.Name,
    new Customer { Name = "C6" },
    new Customer { Name = "RAC" },
    new Customer { Name = "HSBC" }
);
context.SaveChanges();
var customers = context.Customers.ToList();

我将非常感谢这方面的帮助，以便我可以用适当的数据为我的数据库播种。

非常感谢您的帮助，也很抱歉这篇文章很长。

---更新---

在遵循克里斯·普拉特(Chris Pratt(在下面出色的答案之后，我现在得到以下错误： Conflicting changes detected. This may happen when trying to insert multiple entities with the same key.

这是我对种子设定和所有涉及的模型的新代码：https://gist.github.com/jacquibo/c19deb492ec3fff0b5a7

谁能帮忙？

var customers = new[]{
    new Customer { Name = "cust_a" },
    new Customer { Name = "cust_b" },
    new Customer { Name = "cust_c" }
};
context.Customers.AddOrUpdate(r => r.Name, customers[0], customers[1], customers[2]);
context.SaveChanges()

// Default Licenses - create
var licenses = new[]{
    new License { DateCreated = DateTime.Now.AddDays(-3), CustomerId = customers[0].CustomerId },
    new License { DateCreated = DateTime.Now.AddDays(-2), CustomerId = customers[1].CustomerId },
    new License { DateCreated = DateTime.Now.AddDays(-1), CustomerId = customers[2].CustomerId }
};
context.Licenses.AddOrUpdatE(r => r.DateCreated, licenses[0], licenses[1], licenses[2]);

// Changed customer id from customer[1] to customer[0]
new License { DateCreated = DateTime.Now.AddDays(-2), CustomerId = customers[0].CustomerId },

// Attempted to change customer[1] to customer[0], but EF ignores this in the update.
new License { DateCreated = DateTime.Now.AddDays(-2), Customer = customers[0] },

[ForeignKey("Customer")]
public int CustomerId { get; set;}
public virtual Customer Customer { get; set; }

public class License : Entity
{
    [Key, ForeignKey("Customer")]
    public int LicenseId { get; set; } // consider renaming to CustomerId
    // other properties here
    ...
    public virtual Customer Customer { get; set; }
}
public class Customer : Entity
{
    [Key, ForeignKey( "License" )]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int CustomerId { get; set;}
    // other properties here
    ...
    public virtual License License { get; set; }
}