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实体框架一对多,只有一个导航属性:WithRequiredDependant?

ef-fluent-api entity-framework c#

Harald Coppoolse · 技术社区 · 9 年前

MSDN: Entity Framework Fluent API - Relationships :

而不是两者都有。

简化:a School 有很多 Students ; 学校和学生之间存在一对多关系,但学校没有包含学生集合的属性

class Student
{
    public int Id {get; set;}
    // a Student attends one School; foreign key SchoolId
    public int SchoolId {get; set;}
    public School School {get; set;}
}

class School
{
    public int Id {get; set;}
    // missing: public virtual ICollection<Studen> Students {get; set;}
}

OnModelCreating

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<Student>()
        .HasRequired(student => student.School)
        .WithMany(school => school.Students)
        .HasForeignKey(student => student.SchoolId);
}

因为缺乏 School.Students ,我需要做些额外的事情。根据一开始的链接,我似乎不得不与 WithRequiredDependant .

// Summary:
//     Configures the relationship to be required without a navigation property
//     on the other side of the relationship. The entity type being configured will
//     be the dependent and contain a foreign key to the principal. The entity type
//     that the relationship targets will be the principal in the relationship.
//
public ForeignKeyNavigationPropertyConfiguration WithRequiredDependent();

modelBuilder.Entity<Student>()
    .HasRequired(student => student.School)
    .WithRequiredDependent();

我需要什么fluent API?

1 回复 | 直到 9 年前

Henk Holterman 9 年前

我希望我心中有正确的版本:

modelBuilder.Entity<Student>()
    .HasRequired(student => student.School)
  //.WithMany(school => school.Students)
    .WithMany()
    .HasForeignKey(student => student.SchoolId);

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