Question

我收到此错误：查询输入必须至少包含一个表或查询我的代码是：

    using (OleDbConnection myCon = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=timetabledata.accdb")){                       
        OleDbCommand cmd = new OleDbCommand();
        cmd.CommandType = CommandType.Text;
                           string q = "INSERT INTO timehourly (teacherid,subjectid) Values ('@teacherID','@subjid')" + " WHERE hour='@i' AND dayid='@ds'";
                          cmd.Parameters.AddWithValue("@teacherID", Convert.ToInt32(teacher_combo.SelectedValue).ToString());
                           cmd.Parameters.AddWithValue("@subjid",  Convert.ToInt32(subject_combo.SelectedValue).ToString());
                           cmd.Parameters.AddWithValue("@i",i.ToString());
cmd.Parameters.AddWithValue("@ds",ds.Tables[0].Rows[k].ItemArray[0].ToString());
                            cmd.CommandText = q;
        cmd.Connection = myCon;
        myCon.Open();
        cmd.ExecuteNonQuery();
        System.Windows.Forms.MessageBox.Show("successfully added", "Caption", MessageBoxButtons.OKCancel, MessageBoxIcon.Information);}

Answer 1

您需要从参数声明中删除撇号。还要验证传递给查询的值中是否存在数据。在添加参数之前，还要指定CommandText。

此外，您可以在OleDbCommand语句中将using包装在IDisposable语句中，同时实现INSERT。

然后，您尝试使用WHERE子句执行INSERT，这将无效。

UPDATE语句实际上是在表中“插入”一行，不能在已有行的位置插入行。

您要找的是using (OleDbConnection myCon = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=timetabledata.accdb")) using (OleDbCommand cmd = new OleDbCommand()) { cmd.CommandType = CommandType.Text; string q = "UPDATE timehourly SET teacheridh = @teacherId, SET subjectidh = @subjid WHERE hour=@i AND dayid=@ds"; cmd.CommandText = q; cmd.Parameters.AddWithValue("@teacherID", Convert.ToInt32(teacher_combo.SelectedValue).ToString()); cmd.Parameters.AddWithValue("@subjid", Convert.ToInt32(subject_combo.SelectedValue).ToString()); cmd.Parameters.AddWithValue("@i",i.ToString()); cmd.Parameters.AddWithValue("@ds",ds.Tables[0].Rows[k].ItemArray[0].ToString()); cmd.Connection = myCon; myCon.Open(); cmd.ExecuteNonQuery(); System.Windows.Forms.MessageBox.Show("successfully added", "Caption", MessageBoxButtons.OKCancel, MessageBoxIcon.Information); } - 我已经编辑了下面的语法来反映这一点。

INSERT

如果您确实想要WHERE，那么只需从q字符串中取出{{1}}。

获取错误：查询输入必须至少包含一个表或查询

1 个答案: