Question

我有以下类和EF约定创建表 - 一切都很好。现在我想在ToDoList上配置级联删除（这样当我删除ToDoList时，所有ToDoItems和UserToDoLists也会被自动删除）。我必须重新指定EF约定能够检测哪些才能设置WillCascadeOnDelete？如何在流畅的API中指定此关系？

public class ToDoList
{
    public int Id { get; set; }
    public string Description { get; set; }
    public virtual ICollection<ToDoItem> ToDoItems { get; set; }
    public virtual ICollection<UserToDoList> UserToDoLists { get; set; }
}

public class ApplicationUser : IdentityUser
{
    public ApplicationUser()
        : base()
    {
    }

    public virtual ICollection<UserToDoList> UserToDoLists { get; set; }
}

// a todolist can have many users and a user can have many todolist
// junction table will have addition fields
public class UserToDoList
{
    public string UserId { get; set; }
    public virtual ApplicationUser User { get; set; }

    public virtual int ToDoListId { get; set; }
    public virtual ToDoList ToDoList { get; set; }

    // additional fields
    public bool IsOwner { get; set; }
    public int Ordinal { get; set; }
    public bool AllowEdit { get; set; }
}

public class UserToDoListConfig : EntityTypeConfiguration<UserToDoList>
{
    public UserToDoListConfig()
    {
        HasKey(ut => new { ut.UserId, ut.ToDoListId });
    }
}

public class ToDoListConfig : EntityTypeConfiguration<ToDoList>
{
    public ToDoListConfig()
    {
        Property(t => t.Description).IsRequired().HasMaxLength(50);

        HasMany(t =>t.UserToDoLists).??
    }
}

Answer 1

这是从ToDoList到您的联结表UserToDoList的简单的一对多关系，所以您只需设置这样的映射

HasMany(m => m.UserToDoLists)
    .WithRequired(m => m.ToDoList)
    .HasForeignKey(m => m.ToDoListId);

和EF将自动处理您的级联删除，因为在联结表端需要ToDoList。

如何使用EF Fluent API配置级联删除

1 个答案: