使用 Linq web 从多个表中删除行 Api asp.net

Question

public async Task<IHttpActionResult> DeleteUser(string id)
        {
            try {
                using (hospiceEntities db = new hospiceEntities())
                {
                    Guid guid_id = Guid.Parse(id);
                    var q =
                    (from user in db.Users
                     join resource in db.Resources
                     on user.Id equals resource.UserId
                     where user.Id == guid_id
                     select user).Single<User>();

                    foreach (Resource res in q.Resources)
                    {
                        db.Resources.Remove(res);

                    }
                    db.Users.Remove(q);
                    await db.SaveChangesAsync();
                    return Ok(Helper.SuccessResponse("User Deleted"));
                }
            }
            catch (Exception ex)
            {
                return BadRequest(ex.Message);
            }
        }

我有两个表 Users 和 Resource 通过外键约束连接。我已经编写了上面的 LINQ 查询来删除记录，但没有删除它。请告诉我我做错了什么。谢谢

Answer 1

尝试使用此语法包含资源

    var user = await
    db.Users
   .Include(u=>u.Resources)
   .Where(u=> u.Id == guid_id)
   .FirstOrDefaltAsync();

   var res=user.Resources.ToList();
     db.Resources.RemoveRange(res);

    // or try directly
   db.Resources.RemoveRange(user.Resourses);

  //or maybe this is better
     user.Resources==null;
     
     db.Users.Remove(user);
     await db.SaveChangesAsync();

Answer 2

在 foreach 循环中使用它

(db.GetTable<Resource>().DeleteOnSubmit(res));

并使用此代码

db.GetTable<Users>().DeleteOnSubmit(q);  
                    db.SubmitChanges();

而不是(db.Users.Remove(q));

Answer 3

这样解决的：

 public async Task<IHttpActionResult> DeleteUser(string id)
        {
            try {
                using (hospiceEntities db = new hospiceEntities())
                {
                    Guid guid_id = Guid.Parse(id);
                    var deleteuser = db.Users.FirstOrDefault(e => e.Id == guid_id);
                    if (deleteuser == null)
                    {
                        return Content(HttpStatusCode.NotFound, "User Not Found");
                    }
                    else
                    {
                        var q =
                    from user in db.Users
                    join resource in db.Resources
                    on user.Id equals resource.UserId
                    where user.Id == guid_id
                    select new
                    {
                        Users = user,
                        Resources = resource
                    };
                        foreach (var item in q)
                        {
                            db.Resources.Remove(item.Resources);
                            db.Users.Remove(item.Users);
                        }
                        await db.SaveChangesAsync();
                    }
                }
                return Ok(Helper.SuccessResponse("User Deleted"));
            }
            catch (Exception ex)
            {
                return BadRequest(ex.Message);
            }
        }

使用 Linq web 从多个表中删除行 Api asp.net

Delete Rows from multiple tables using Linq web Api asp.net

c#

linq

cascade

http-delete

asp.net-web-api