Csharp 在多对多关系上不删除实体

我正在try 删除SentGroupJoinRequest记录 record of userId and GroupJoinRequestId

这是由User实体和SentGroupJoinRequests字段之间的关系和按JoinRequests字段分组创建的，但当访问和删除每个实体的属性时，它们不会从表中删除. 以下是方法:

public async Task<ServiceResponse<string>> AcceptJoinRequest(int groupId, string memberId)
        {
            var serviceResponse = new ServiceResponse<string>();
            try
            {
                var group = await _context.Groups.FindAsync(groupId) ?? throw new Exception("Group not found.");

                if (group.OwnerId != _http.HttpContext.User.FindFirstValue("Id"))
                {
                    throw new Exception("You are not group owner.");
                }
                var userRequest = await _context.Users.FindAsync(memberId) ?? throw new Exception("User not found.");
                if (group.Followers.Contains(userRequest))
                {
                    throw new Exception("User already in a group.");
                }
                group.Followers.Add(userRequest);
                userRequest.Groups.Add(group);
                userRequest.SentGroupJoinRequests.Remove(group);
                
                group.JoinRequests.Remove(userRequest);
                await _context.SaveChangesAsync();
                serviceResponse.Message = "You have approved the application.";
                serviceResponse.Success = true;
            }
            catch (Exception ex)
            {
                serviceResponse.Success = false;
                serviceResponse.Message = ex.Message;
            }
            return serviceResponse;
        }

User个实体:

namespace SocialNetwork.Entities
{
    public class User
    {
        public string Id { get; set; } = string.Empty;
        public string Surname { get; set; } = string.Empty;
        public string Name { get; set; } = string.Empty;
        public DateTime Birthday { get; set; }
        public string Location { get; set; } = string.Empty;
        public List<Group> Groups { get; set; } = [];
        public List<Group> SentGroupJoinRequests { get; set; } = [];
    }
}

Group个实体:

namespace SocialNetwork.Entities
{
    public class Group
    {
        public int Id { get; set; }
        public string OwnerId { get; set; } = string.Empty;
        public string Name { get; set; } = string.Empty;
        public string Description { get; set; } = string.Empty;
        public List<Post> Posts { get; set; } = [];
        public List<User> Followers { get; set; } = [];
        public List<User> JoinRequests { get; set; } = [];
        public bool IsClosed { get; set; }
    }
}

数据库设置:

namespace SocialNetwork.Data
{
    public class DataContext : DbContext
    {
        public DataContext(DbContextOptions<DataContext> options) : base(options)
        {
        }

        public DbSet<User> Users { get; set; }
        public DbSet<MetaData> MetaDatas { get; set; }
        public DbSet<Post> Posts { get; set; }
        public DbSet<Group> Groups { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<User>()
                .HasMany(u => u.Groups)
                .WithMany(f => f.Followers)
                .UsingEntity(j => j.ToTable("UserGroups"));

            modelBuilder.Entity<User>()
                .HasMany(u => u.SentGroupJoinRequests)
                .WithMany(j => j.JoinRequests)
                .UsingEntity(j => j.ToTable("UserJoinRequests"));
        }
    }
}

为什么没有在UserJoinRequest表中删除该字段，我如何解决它？

数据库中的记录不会被删除，即使您分别从不同实体中删除了两个属性