Question

我有一个带有2个表NewSubject和NewStudentInfo的Access数据库，它们也有关系。我想更新NewSubject中的字段，但它不起作用。该怎么办？谢谢。见下图。

2个不同的更新代码但不起作用。

如果我将此代码与Concatenate一起使用，MessageBox将弹出并显示“已更新”，但显然它不会更新数据库。我会在证明代码后附上一些图片。

string conn = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\Projects\Betches\MiniThesis\MACInfo\MACInfo\bin\Debug\Database\MasterList.accdb";
        string query = "UPDATE NewSubjects SET StudentID = '" + maskedTextBox1.Text + "',SubjectCode = '" + TextBoxSubjectCode.Text + "',SubjectDescription = '" + TextBoxSubjectDesc.Text + "',Unit = '" + TextBoxUnit.Text + "',SubjectGrade = '" + TextBoxSubjectGrade.Text + "',Course = '" + TextBoxCourse.Text + "',AcademicYear = '" + TextBoxYear.Text + "',Semester = '" + TextBoxSemester.Text + "' WHERE StudentID = '" + maskedTextBox1.Text + "';";
        OleDbConnection connection = new OleDbConnection(conn);
        OleDbCommand command1 = new OleDbCommand(query, connection);
        OleDbDataReader myReader;
        try
        {
            connection.Open();
            myReader = command1.ExecuteReader();
            MessageBox.Show("Updated!","MACInfo",MessageBoxButtons.OK,MessageBoxIcon.Information);
            Loader();
            while (myReader.Read())
            {

            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }

注意：我正在尝试更新第一行，第3列是SubjectCode。 Concat Code Image Proof CLICK ME! CLICK ME FOR Database

如果我要使用Parameters.AddWithValue，它将不会更新数据库，它将显示消息框说“更新不成功！”但代码没有错误。页脚上附有图像以供证明。

            OleDbConnection conn = new OleDbConnection(@"Provider=M1icrosoft.ACE.OLEDB.12.0;Data Source=D:\Projects\Betches\MiniThesis\MACInfo\MACInfo\bin\Debug\Database\MasterList.accdb");
        command = conn.CreateCommand();
        command.CommandText = @"UPDATE NewSubjects SET [StudentID] = @Sid,
            [SubjectCode] = @Sc,
            [SubjectDescription] = @Sd,
            [Unit] = @Un,
            [SubjectGrade] = @Sg,
            [Course] = @Crs,
            [AcademicYear] = @Yr,
            [Semester] = @Sem WHERE [StudentID] = @Sid";
        command.Parameters.AddWithValue("@Sid", maskedTextBox1.Text);
        command.Parameters.AddWithValue("@SC", TextBoxSubjectCode.Text);
        command.Parameters.AddWithValue("@Sd", TextBoxSubjectDesc.Text);
        command.Parameters.AddWithValue("@Un", TextBoxUnit.Text);
        command.Parameters.AddWithValue("@Sg", TextBoxSubjectGrade.Text);
        command.Parameters.AddWithValue("@Crs", TextBoxCourse.Text);
        command.Parameters.AddWithValue("@Yr", TextBoxYear.Text);
        command.Parameters.AddWithValue("@Sem", TextBoxSemester.Text);

        conn.Open();
        int rowsAffected = command.ExecuteNonQuery();
        if (rowsAffected != 0)
        {
            MessageBox.Show("Update Successful!", "MACInfo", MessageBoxButtons.OK, MessageBoxIcon.Information);
            Loader();
            TextBoxSubjectCode.Enabled = false;
            TextBoxSubjectDesc.Enabled = false;
            TextBoxUnit.Enabled = false;
            TextBoxSubjectGrade.Enabled = false;
            TextBoxCourse.Enabled = false;
            TextBoxYear.Enabled = false;
            TextBoxSemester.Enabled = false;
        }
        else
        {
            MessageBox.Show("Error");
        }
        conn.Close();

Update Unsuccessful using Parameters.AddWithValue

如何更新与另一个表的关系表

0 个答案: