数据库更新查询不起作用VB.Net

我的查询插入和选择工作正常 . 但更新不起作用 . 没有错误，但数据库不会更新 . 这是代码Dim连接As New OleDbConnection（“Provider = Microsoft.ACE.OLEDB.12.0; Data Source = C：\ Users \ TMJ \ Documents \ Database1.accdb”）Dim命令As OleDbCommand

connection.Open()
    command = New OleDbCommand("UPDATE Students SET first_name=@fname,middle_name=@mname,last_name=@lname,add_line1=@add1,add_line2=@add2,add_line3=@add3,dob=@bd,gender=@gen,f_first_name=@fname1,f_middle_name=@fname2,f_last_name=@fname3,f_occupation=@fjob,m_first_name=@mname1,m_middle_name=@mname2,m_last_name=@mname3,m_occupation=@mjob,date_enrolled=@de,class=@clas,subject1=@sub1,subject2=@sub2,subject3=@sub3,additional_details=@ad WHERE Admission_no=@adno; ", connection)
    command.Parameters.Add("@adno", OleDbType.Integer).Value = txt_adno.Text
    command.Parameters.Add("@fname", OleDbType.VarWChar).Value = txt_stdname1.Text
    command.Parameters.Add("@mname", OleDbType.VarWChar).Value = txt_stdname2.Text
    command.Parameters.Add("@lname", OleDbType.VarWChar).Value = txt_stdname3.Text
    command.Parameters.Add("@add1", OleDbType.VarWChar).Value = txt_address1.Text
    command.Parameters.Add("@add2", OleDbType.VarWChar).Value = txt_address2.Text
    command.Parameters.Add("@add3", OleDbType.VarWChar).Value = txt_address3.Text
    command.Parameters.Add("@bd", OleDbType.Date).Value = date_dob.Value
    command.Parameters.Add("@gen", OleDbType.VarWChar).Value = cmb_gender.Text
    command.Parameters.Add("@fname1", OleDbType.VarWChar).Value = txt_FName1.Text
    command.Parameters.Add("@fname2", OleDbType.VarWChar).Value = txt_FName2.Text
    command.Parameters.Add("@fname3", OleDbType.VarWChar).Value = txt_FName3.Text
    command.Parameters.Add("@fjob", OleDbType.VarWChar).Value = txt_FOccupation.Text
    command.Parameters.Add("@mname1", OleDbType.VarWChar).Value = txt_MName1.Text
    command.Parameters.Add("@mname2", OleDbType.VarWChar).Value = txt_MName2.Text
    command.Parameters.Add("@mname3", OleDbType.VarWChar).Value = txt_MName3.Text
    command.Parameters.Add("mjob", OleDbType.VarWChar).Value = txt_MOccupation.Text
    command.Parameters.Add("@de", OleDbType.Date).Value = dtpDateEnrolled.Value
    command.Parameters.Add("@clas", OleDbType.VarWChar).Value = cmbclass.Text
    command.Parameters.Add("@sub1", OleDbType.VarWChar).Value = cmbsubject1.Text
    command.Parameters.Add("@sub2", OleDbType.VarWChar).Value = cmbsubject2.Text
    command.Parameters.Add("@sub3", OleDbType.VarWChar).Value = cmbsubject3.Text
    command.Parameters.Add("@ad", OleDbType.VarWChar).Value = txtlastSchool.Text


    command.ExecuteNonQuery()
    connection.Close()