如何在 ASP.NET MVC 中映射多个一对多关系？

Question

我有几个域模型 - Address、Customer、Employee、StoreLocation。 Address 与 Customer 和 Employee 具有多对一关系，与 StoreLocation 具有一对一关系。

public class Address
{
    public int Id;
    public string Line1 { get; set; }
    public string Line2 { get; set; }
    public string Line3 { get; set; }
}

public class Customer
{
    public int Id { get; set; }
    public string Name { get; set; }
    public IList<Address> Addresses { get; set; }
}

public class StoreLocation
{
    public int Id { get; set; }
    public string ShortCode { get; set; }
    public string Description { get; set; }
    public Address Address { get; set; }
}


public class Employee
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTime Dob { get; set; }
    public IList<Address> Addresses { get; set; }
}

如何映射这种关系？我正在使用 ASP.NET MVC 3.0 和 Entity Framework 4.1。

Answer 1

如果您使用代码优先（我认为您想要这个，否则，您必须编辑您的 Q），第一种方法是下面解释的方法：

Entities:

public class Address {
    [Key]
    public int Id { get; set; }
    public string Line1 { get; set; }
    public string Line2 { get; set; }
    public string Line3 { get; set; }

    public virtual Customer Customer { get; set; }
    public virtual StoreLocation StoreLocation { get; set; }
    public virtual Employee Employee { get; set; }

    public int? CustomerId { get; set; }

    public int? EmployeeId { get; set; }
}

public class Customer {
    [Key]
    public int Id { get; set; }
    public string Name { get; set; }
    public virtual ICollection<Address> Addresses { get; set; }
}

public class StoreLocation {
    [Key]
    public int Id { get; set; }
    public string ShortCode { get; set; }
    public string Description { get; set; }
    public virtual Address Address { get; set; }
}


public class Employee {
    [Key]
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTime Dob { get; set; }
    public virtual ICollection<Address> Addresses { get; set; }
}

DbContext继承类：

public class ManyOneToManyContext : DbContext {

    static ManyOneToManyContext() {
        Database.SetInitializer<ManyOneToManyContext>(new ManyOneToManyInitializer());
    }

    public DbSet<Address> Addresses { get; set; }
    public DbSet<Customer> Customers { get; set; }
    public DbSet<StoreLocation> StoreLocations { get; set; }
    public DbSet<Employee> Employees { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder) {

        modelBuilder.Conventions.Remove<IncludeMetadataConvention>();

        modelBuilder.Entity<Customer>().HasMany(c => c.Addresses).WithOptional(a => a.Customer).HasForeignKey(a => a.CustomerId);

        modelBuilder.Entity<StoreLocation>().HasRequired(s => s.Address).WithOptional(a => a.StoreLocation).Map(t => t.MapKey("AddressId"));

        modelBuilder.Entity<Employee>().HasMany(e => e.Addresses).WithOptional(a => a.Employee).HasForeignKey(e => e.EmployeeId);
    }
}

上下文初始化程序：

public class ManyOneToManyInitializer : DropCreateDatabaseAlways<ManyOneToManyContext> {
    protected override void Seed(ManyOneToManyContext context) {

    }
}

这将创建以下数据库模式：

如果您对任何部分有任何疑问或需要澄清，请告诉我。