อยากทราบหลักการเขียนโปรแกรมติดต่อ Database ไม่ให้เกิด Timeout ว่ามีหลักการอะไรบ้าง

Dim s As New Sira
        Dim intLineNo As Integer
        Select Case ddlLname.Text
            Case "Trim 1"
                intLineNo = "1"
            Case "Trim 2"
                intLineNo = "2"
            Case "IP"
                intLineNo = "3"
            Case "Door"
                intLineNo = "4"
            Case "Chassis 1"
                intLineNo = "5"
            Case "Chassis 2"
                intLineNo = "6"
            Case "Frame 1"
                intLineNo = "7"
            Case "Frame 2"
                intLineNo = "8"
            Case "Engine"
                intLineNo = "9"
            Case "Axle"
                intLineNo = "10"
            Case "Final 1"
                intLineNo = "11"
            Case "Final 2"
                intLineNo = "12"
            Case "Final 3"
                intLineNo = "13"
            Case "Inspection"
                intLineNo = "14"

        End Select
        Dim strStime As String = ddlSmonth.Text & "/" & ddlSday.Text & "/" & ddlSyear.Text & " " & ddlTper0.Text & ":00"
        Dim strEtime As String = ddlEmonth.Text & "/" & ddlEday.Text & "/" & ddlEyear.Text & " " & ddlTper1.Text & ":00"

        Dim strSQL As String = "select case c.intLineNo when '1' then 'Trim 1' when '2' then 'Trim 2' when '3' then 'IP' when '4' then 'Door' when '5' then 'Chassis 1' when '6' then 'Chassis 2' when '7' then 'Frame 1' when '8' then 'Frame 2' when '9' then 'Engine' when '10' then 'Axle' when '11' then 'Final 1' when '12' then 'Final 2' when '13' then 'Final 3' when '14' then 'Inspection' end as intLineNo " & _
                                ", c.intToolID as intQID , c.strToolName as strEquipName , c.intStationNo , c.strLineSide " & _
                                ", case (d.intJudgementResult1 + d.intJudgementResult2 + d.intJudgementResult3 + d.intJudgementResult4 + d.intJudgementResult5) when '160' then 'OK' when '320' then 'NG' end as Pass " & _
                                "from (ToolConfig as c inner join PokayokeToolLog as h on c.intLineNo = h.intLineNumber) " & _
                                "inner join PokayokeQualityResultLog as d on h.intToolLogID = d.intToolLogID " & _
                                "where h.datInsertTimestamp >= '" & strStime & "' and h.datInsertTimestamp <= '" & strEtime & "' and c.intLineNo = '" & intLineNo.ToString & "' and c.bitEnabled = 'true'"

        DV = s.GetDataTable(strSQL).DefaultView
        gvShow.DataSource = DV
        gvShow.DataBind()