如果我在 class 中更改父实体的导航属性，是否需要手动更改外键？

Question

我有一个 Entity;

public class ChildEntity
{
    /// <summary>
    /// Foreign key for this entity.
    /// </summary>
    public virtual int ParentId { get; set; }

    /// <summary>
    /// Navigation Property for this entity.
    /// </summary>
    public virtual TParentEntity Parent { get; set; }
}

如果我在数据库中将 Parent 属性更改为不同的 ParentEntity，（同时更新 Parents Collections 和 Children Entities) 然后我需要手动将 ParentId 从一个父实体更改为另一个父实体吗？

谢谢！

Answer 1

If you change the navigation property of an entity, the corresponding changes will be made to the foreign key column in the database.

来源：https://docs.microsoft.com/en-us/ef/core/saving/related-data#changing-relationships

这是观察上述行为的示例代码。

using (var context = new Context())
{
    var child = new ChildEntity();
    child.Parent = new TParentEntity();
    context.Add(child);

    context.SaveChanges();
    Console.WriteLine(child.ParentId); // ParentId == 1

    child.Parent = new TParentEntity();
    Console.WriteLine(child.ParentId); // ParentId == 1

    context.SaveChanges();
    Console.WriteLine(child.ParentId); // ParentId == 2
}

如果我在 class 中更改父实体的导航属性，是否需要手动更改外键？

If I change the Navigation Property for the Parent Entity in a class, do I need to manually change the Foreign Key?

c#

database

entity-framework

code-first

如果我在 class 中更改父实体的导航 属性，是否需要手动更改外键？

If I change the Navigation Property for the Parent Entity in a class, do I need to manually change the Foreign Key?

c#

database

entity-framework

code-first

如果我在 class 中更改父实体的导航属性，是否需要手动更改外键？