首先通过 Fluent API 在 EF 代码中实现零或一到零或一的关系

问题描述

我有两个 POCO 课程:

I have two POCO classes:

订单类:

public class Order
{
    public int Id { get; set; }
    public int? QuotationId { get; set; }
    public virtual Quotation Quotation { get; set; }
    ....
}

引用类:

public class Quotation
{
    public int Id { get; set; }
    public virtual Order Order { get; set; }
    ....
}

• 每个Order 可以由一个或零个引用构成，并且
• 每个报价可能导致订单.
• Each Order may be made from one or zero quotation, and
• each quotation may cause an order.

所以我有一个一或零"到一或零"关系，如何在 EF Code first by Fluent API 中实现这一点?

So I have an "one or zero" to "one or zero" relation, how can I implement this, in EF Code first by Fluent API?

推荐答案

通过将 pocos 更改为:

By changing pocos to:

public class Order
{
    public int OrderId { get; set; }
    public virtual Quotation Quotation { get; set; }
}
public class Quotation
{
    public int QuotationId { get; set; }
    public virtual Order Order { get; set; }
}

并使用这些映射文件:

public class OrderMap : EntityTypeConfiguration<Order>
{
    public OrderMap()
    {
        this.HasOptional(x => x.Quotation)
            .WithOptionalPrincipal()
            .Map(x => x.MapKey("OrderId"));
    }
}

public class QuotationMap : EntityTypeConfiguration<Quotation>
{
    public QuotationMap()
    {
        this.HasOptional(x => x.Order)
            .WithOptionalPrincipal()
            .Map(x => x.MapKey("QuotationId"));
    }
}

我们将拥有这个数据库(即 0..1-0..1):

we will have this DB(that means 0..1-0..1):

特别感谢 (Vahid Nasiri 先生)

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