Trouble with database connections

Trouble with database connections

• bergeron

  as in:
  Dim myQuery1 As String = "SELECT [BID]FROM Table1 WHERE [Date]='" + query + "'"
  or
  Dim myQuery1 As String = "SELECT [BID]FROM Table1 WHERE [Date]=#" + query + "#"
  
  
  because both ways, the messagebox is only showing "S"
  
  
  

• NickNotYet

  hmm, why isn't it even reading I'm sorry, but I completely don't understand what's going on.
  
  Sorry for being such a nube
  -Robert
  
  
  

• CrazyEye

  it's throwing the exception:
  Unhandles exception has occured in your application. If you click Continue, the application will ignore this error and attempt to continue. if you quit, the application will close immediately.
  
  See the end of this message for details on invoking
  just-in-time (JIT) debugging instead of this dialog box.
  
  

  ************** Exception Text **************

  System.InvalidOperationException: No data exists for the row/column.

  at System.Data.OleDb.OleDbDataReader.DoValueCheck(Int32 ordinal)

  at System.Data.OleDb.OleDbDataReader.GetString(Int32 ordinal)

  at mcmorrow_chooser.Form1.Button1_Click(Object sender, EventArgs e) in C:\Documents and Settings\Robert \Local Settings\Application Data\Temporary Projects\mcmorrow chooser\Form1.vb:line 17

  at System.Windows.Forms.Control.OnClick(EventArgs e)

  at System.Windows.Forms.Button.OnClick(EventArgs e)

  at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)

  at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)

  at System.Windows.Forms.Control.WndProc(Message& m)

  at System.Windows.Forms.ButtonBase.WndProc(Message& m)

  at System.Windows.Forms.Button.WndProc(Message& m)

  at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)

  at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)

  at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

  it goes on, but i think that's pretty much the most important part
  
  
  

• Quinn01

  In addition to Ken's suggestion you should also get the string from the field of the reader not the reader itself...such as:

  MyReader(0).ToString

  or

  Cstr(MyReader(0))

  
  
  

• sofakng

  Robert3234 wrote:

  as in: Dim myQuery1 As String = "SELECT [BID]FROM Table1 WHERE [Date]='" + query + "'" or Dim myQuery1 As String = "SELECT [BID]FROM Table1 WHERE [Date]=#" + query + "#" because both ways, the messagebox is only showing "S"

  NO.....From Your query string you need to include pound signs like this:

  Dim query As String = "#" + MonthCalendar1.SelectionStart + "# "...

  
  
  

• russ_mac

  OK, sorry to be consitsantly and persitatantly annoying, but debut exposes doubt, and as I tried out another string...
  
  when i try to use this string
  
  Dim query As String = MonthCalendar1.SelectionStart
  
  Dim time As String = ComboBox1.Text + ComboBox2.Text + " " + ComboBox3.Text
  MsgBox(time)
  Dim myQuery1 As String = "SELECT [Renter]FROM Table1 WHERE [Date]=#" + MonthCalendar1.SelectionStart + "# AND [Time]=#" + time + "#"
  
  and i try to use
  MsgBox(CStr(myReader1(0))) to display it, the program throws an exception at the messagebox line!
  
  it should be returning a string, but instead i get an exception.
  
  sorry for being such a dweeb / annoyance / noob.
  
  -Robert
  
  
  

• hye_heena

  here's my code, by the way
  
  Dim query As String = MonthCalendar1.SelectionStart
  
  Dim time As String = ComboBox1.Text + ComboBox2.Text + " " + ComboBox3.Text
  MsgBox(time)
  Dim myQuery1 As String = "SELECT [Renter]FROM Table1 WHERE [Date]=#" + MonthCalendar1.SelectionStart + "# AND [Time]=#" + time + "#"
  Dim myConn1 As OleDbConnection = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Documents and Settings\Robert\Desktop\Mcmorrow.mdb")
  Dim myCommand1 As OleDbCommand = New OleDbCommand(myQuery1, myConn1)
  myConn1.Open()
  Dim myReader1 As OleDbDataReader = myCommand1.ExecuteReader(CommandBehavior.CloseConnection)
  myReader1.Read()
  'MsgBox(CStr(myReader1(0)))
  If myReader1.Read Then
  MsgBox(myReader1.GetString(0).ToString)
  End If
  
  
  

• George Waters

  In a query you should enclose dates in #
  
  
  

• danni123

  WHat exception is being thrown Somehting about using the reader when the connection is closed maybe...also what is the datatype of the field that you are quering IS it date, time, datetime
  
  

• Kevin Kelly101

  you are not getting any databack that is why you are getting the error.
  
  if myreader1.read then
  dim robert as .........
  end if
  
  
  
  
• Trouble with database connections