在 SET 子句 > 或 INSERT 的列列表中多次指定列名 'userid'

Question

我最近多次遇到这个错误，现在又出现了。早些时候，我最终重写了几乎所有代码。现在我更想知道为什么会这样。这是错误：

The column name 'userid' is specified more than once in the SET clause or column list of an INSERT. A column cannot be assigned more than one value in the same clause. Modify the clause to make sure that a column is updated only once. If this statement updates or inserts columns into a view, column aliasing can conceal the duplication in your code.

这是我的控制器：

[HttpPost]
//[Route("api/Ratings/PostRating/")]
public async Task<ActionResult<Ratings>> PostRating([FromBody] JObject RatingInfo )
{
    
    int id = (int)RatingInfo["id"];
    int val = (int)RatingInfo["val"];
    //Guid userid = Guid.Parse(User.FindFirstValue(ClaimTypes.NameIdentifier));
    //Guid _userid = Guid.Parse("27E72CE4-FC2L-4C18-A27E-974CB4F4448D");
    if (val > 1 || val < 0)
    {
        BadRequest();
    }
    var ratings = await _context.Ratings.FindAsync(id);

    if (ratings == null)
    {
        var newRating = new Ratings();
        //Does not exist
        newRating.Type = "Books";
        newRating.Rating = val;
        newRating.Bookid = id;
        //newRating.Userid = userid;
        _context.Ratings.Add(newRating);
        await _context.SaveChangesAsync();
    }
    else
    {
        //Does exist
        ratings.Active = val;
        _context.Entry(ratings).Property("Active").IsModified = true;


        await _context.SaveChangesAsync();
    }

    return Ok();
    //await _context.SaveChangesAsync();
    //return CreatedAtAction("GetRatings", new { id = ratings.Id }, ratings);
}

这条错误信息是什么意思？为什么我什至不声明用户标识就得到它？

当我遇到 google 这个问题时，他们很少使用 Linq/lambda。

编辑：因为我在class里找到了解决办法，所以我把原来的class也贴在这里：

public partial class Ratings
{
    public int Id { get; set; }
    public int? Bookid { get; set; }
    public string Type { get; set; }
    public int Rating { get; set; }
    public Guid Userid { get; set; }
    public string Subject { get; set; }
    public DateTime Createdon { get; set; }
    public DateTime? Modifiedon { get; set; }
    public int Active { get; set; }

    public virtual Users User { get; set; }
}

Answer 1

我找到了解决方案。问题是一个相关的实体，它也连接了一个用户标识。所以这是两个不在同一个 table 中的用户标识，但是 ef 找到了两个。注释掉相关的 table 就解决了。

public partial class Ratings
{
    public int Id { get; set; }
    public int? Bookid { get; set; }
    public string Type { get; set; }
    public int Rating { get; set; }
    public Guid Userid { get; set; }
    public string Subject { get; set; }
    public DateTime Createdon { get; set; }
    public DateTime? Modifiedon { get; set; }
    public int Active { get; set; }

    //public virtual Users User { get; set; }
}

在 SET 子句 > 或 INSERT 的列列表中多次指定列名 'userid'

The column name 'userid' is specified more than once in the SET clause > or column list of an INSERT

linq

lambda

.net-core

asp.net-core

webapi