Question

public static void DeleteThreads(int threadID)
{
    StringBuilder sb = new StringBuilder();
    sb.Append("DELETE FROM dbo.Threads");
    sb.Append(" WHERE ThreadsID=@ThreadsID");

    string myConnectionString = AllQuestionsPresented.connectionString;

    using (SqlConnection myConnection = new SqlConnection(myConnectionString))
    {
        myConnection.Open();
        SqlCommand sqlCommand = new SqlCommand(sb.ToString(), myConnection);
        sqlCommand.Parameters.Add("@ThreadsID", SqlDbType.Int);
        sqlCommand.Parameters["@ThreadsID"].Value = threadID;
        sqlCommand.ExecuteNonQuery();

    }
}

它给了我这个错误：

The DELETE statement conflicted with the REFERENCE constraint "FK_Comments_Threads". The conflict occurred in database "model", table "dbo.Comments", column 'ThreadsID'.

声明已经终止。

这是否应该修复该错误：

enter code here  public static void DeleteComments(int threadID)
{
    StringBuilder sb = new StringBuilder();
    sb.Append("DELETE FROM dbo.Comments");
    sb.Append(" WHERE ThreadsID=@ThreadsID");

    string myConnectionString = AllQuestionsPresented.connectionString;

    using (SqlConnection myConnection = new SqlConnection(myConnectionString))
    {
        myConnection.Open();
        SqlCommand sqlCommand = new SqlCommand(sb.ToString(), myConnection);
        sqlCommand.Parameters.Add("@ThreadsID", SqlDbType.Int);
        sqlCommand.Parameters["@ThreadsID"].Value = threadID;
        sqlCommand.ExecuteNonQuery();

    }
}

Answer 1

您没有空格，看起来您错过了FROM关键字。

尝试：

sb.Append("DELETE FROM dbo.Threads");    
sb.Append(" WHERE ThreadsID=@ThreadsID");

此外，对于记录：由于将应用程序与数据库紧密耦合，因此使用内联SQL通常很糟糕。如果此应用程序用于任何严重目的，您应该使用单独的数据访问层。

Answer 2

包含“发件人”和空格

 StringBuilder sb = new StringBuilder();
        sb.Append("DELETE from  dbo.Threads ");
        sb.Append("WHERE ThreadsID=@ThreadsID");

Answer 3

你忘记在第一个语句后给空格，忘记添加FROM那个。

StringBuilder sb = new StringBuilder();
sb.Append("DELETE FROM  dbo.Threads  ");
sb.Append(" WHERE ThreadsID=@ThreadsID");

Answer 4

自己构建字符串以查看错误。结果将是

DELETE dbo.ThreadsWHERE ThreadsID=@ThreadsID

您在dbo.Threads之后缺少FROM关键字和空格。

sb.Append("DELETE FROM dbo.Threads ");    
sb.Append("WHERE ThreadsID=@ThreadsID");

Answer 5

应该是

DELETE FROM ......

Answer 6

ThreadsID作为注释和其他表上的forign键传递，您必须删除首先与该ThreadID关联的记录。您可以从SQL Server Management Stidio在主表上设置级联删除选项。

删除语句有问题

6 个答案: