实体创建外键

Question

我试图首先使用实体​​和代码添加外键关系。 我有以下简化的设置。

public class ChildClass
{
    public int SId { get; set; }
    [ForeignKey("SId")]
    public ParentClass Parent { get; set; }
}

public class ParentClass
{       
    [Key]
    public int SId { get; set; }      
    public ChildClass Child { get; set; }
}

当我尝试添加迁移时，出现以下错误。

Unable to determine the principal end of an association between the types 'ChildClass' and 'ParentClass'. The principal end of this association must be explicitly configured using either the relationship fluent API or data annotations.

Answer 1

如果您希望ChildClass SId属性ChildClass PK又是FK，则应尝试以下操作：

    public class ChildClass
    {
        [Key, ForeignKey("Parent")]
        public int SId { get; set; }

        public ParentClass Parent { get; set; }
    }

    public class ParentClass
    {
        [Key]
        public int SId { get; set; }

        public ChildClass Child { get; set; }
    }

创建的表：

家长：

小孩：