Database Connection is Not Ending - vb.net

Question

I have the following code to insert some data from a GridView to a oracle database.
Protected Sub btnInsert_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnInsert.Click
Dim con = New OleDbConnection("Data Source=sml2; User ID=sfpl; Password=a; provider=OraOLEDB.Oracle")
con.Open()
For Each gvRow As GridViewRow In GridView1.Rows
Dim trndate As Date = ddlTrnDte.SelectedValue
Dim ZoneNo As Integer = ddlZone.SelectedValue
Dim DocNo As TextBox = CType(gvRow.FindControl("txtDocNo"), TextBox)
Dim VehCod As DropDownList = CType(gvRow.FindControl("ddlVeh"), DropDownList)
Dim CircleNo As DropDownList = CType(gvRow.FindControl("ddlCircle"), DropDownList)
Dim Contractor As DropDownList = CType(gvRow.FindControl("ddlContractor"), DropDownList)
Dim Supplier As DropDownList = CType(gvRow.FindControl("ddlSupplier"), DropDownList)
Dim NetWt As TextBox = CType(gvRow.FindControl("txtNetWt"), TextBox)
Dim Rate As TextBox = CType(gvRow.FindControl("txtRate"), TextBox)
Dim SNF As TextBox = CType(gvRow.FindControl("txtSNF"), TextBox)
Dim FAT As TextBox = CType(gvRow.FindControl("txtFAT"), TextBox)
Dim LR As TextBox = CType(gvRow.FindControl("txtLR"), TextBox)
Dim TS As TextBox = CType(gvRow.FindControl("txtTS"), TextBox)
'Create Connection
Dim cmd As OleDbCommand = New OleDbCommand("Insert into MLK_02_01 (TRN_DTE,ZONE_NO,CIRCLE_NO,CNT_NO,DOC_NO,SUP_COD,VEH_NUM,NET_WEIGHT,Q_SNF,Q_FAT,Q_LR,Q_TS,RATE,veh_cod) VALUES (:TRN_DTE,:ZONE_NO,:CIRCLE_NO,:CNT_NO,:DOC_NO,:SUP_COD,:VEH_NUM,:NET_WEIGHT,:Q_SNF,:Q_FAT,:Q_LR,:Q_TS,:RATE,:veh_cod)", con)
cmd.Parameters.Clear()
'TrnDate
cmd.Parameters.Add(":trn_dte", (OleDb.OleDbType.Date))
cmd.Parameters(":trn_dte").Value = DateTime.Now()
cmd.Parameters(":trn_dte").Value = ddlTrnDte.SelectedValue
cmd.Parameters.AddWithValue(":ZONE_no", ZoneNo)
cmd.Parameters.AddWithValue(":CIRCLE_no", CircleNo.SelectedValue)
cmd.Parameters.AddWithValue(":CNT_no", Contractor.SelectedValue)
cmd.Parameters.AddWithValue(":Doc_No", DocNo.Text)
cmd.Parameters.AddWithValue(":sup_cod", Contractor.SelectedValue)
cmd.Parameters.AddWithValue(":Veh_num", VehCod.SelectedItem.Text)
cmd.Parameters.AddWithValue(":NET_WEIGHT", NetWt.Text)
cmd.Parameters.AddWithValue(":Q_SNF", SNF.Text)
cmd.Parameters.AddWithValue(":Q_FAT", FAT.Text)
cmd.Parameters.AddWithValue(":Q_LR", LR.Text)
cmd.Parameters.AddWithValue(":Q_TS", TS.Text)
cmd.Parameters.AddWithValue(":rate", Rate.Text)
cmd.Parameters.AddWithValue(":veh_cod", VehCod.SelectedValue)
cmd.ExecuteNonQuery()
Label1.Text = "All Records are Saved Successfully"
con.Close()
btnInsert.Enabled = False
Next
End Sub
Data is inserted into database fine but when the form is closed the database connection does not end. I need help in ending the database session to eliminate further communication errors.

Answer 1

You mention it's a page, so I'm assuming this is an ASP page.
IIS has database connection pooling enabled by default. This means that even though your code closed your connection, IIS maintains a connection in order to make the next query from the next request execute faster.
To disable connection pooling, in your database connection string add this:
Pooling=false
New OleDbConnection("Data Source=sml2; User ID=sfpl; Password=a; provider=OraOLEDB.Oracle; Pooling=false")
Also, after your execute change to this:
cmd.ExecuteNonQuery()
cmd.Dispose()
After the con.Close():
con.Close()
con.Dispose()
and that should dispose the command and connection objects.