循环与数据库（数据表对象不参考）ASP.NET VB

Question

我有代码循环通过数据表并将它们插入数据库。数据在第一个循环中插入正确，但它复制了循环的其余部分。所以我最终在db中重复了相同的数据。

Dim custID As Integer 
    Dim objDT As System.Data.DataTable 
    Dim objDR As System.Data.DataRow 

Sub Page_Load 



End Sub 

'store customer info' 
Sub btTest_Click(sender As Object, e As EventArgs) 



    Dim con As New System.Data.OleDb.OleDbConnection 

    Dim myPath As String 
    myPath = Server.MapPath("faraxday.mdb") 

    con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data source=" & myPath & ";" 
    Dim myCommand As New System.Data.OleDb.OleDbCommand 

    myCommand.CommandText = "INSERT INTO customer(name, address_1, address_2, postcode, email, pass) values('" & name.Text & "','" & address_1.Text & "','" & address_2.Text & "','" & postcode.Text & "','" & email.Text & "','" & pass.Text & "')" 
    myCommand.Connection = con 
    con.Open() 
    myCommand.ExecuteNonQuery() 
    con.Close() 

    GetID() 
    recordOrder() 


End Sub 


'get customer id' 
Function GetID() As System.Data.DataSet 

    Dim con As New System.Data.OleDb.OleDbConnection 

    Dim myPath As String 
    myPath = Server.MapPath("faraxday.mdb") 

    con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data source=" & myPath & ";" 

    Dim adp As New System.Data.OleDb.OleDbDataAdapter("SELECT customer_id FROM customer ORDER BY customer_id DESC", con) 

    Dim dt As New System.Data.DataTable 
    adp.Fill(dt) 

    custID = dt.Rows(0).Item("customer_id") 
End Function 

'Add items to db' 
Function recordOrder() 
    objDT = Session("Cart") 


    Dim intCounter As Integer 
    Dim con2 As New System.Data.OleDb.OleDbConnection 
    Dim myPath2 As String 
    myPath2 = Server.MapPath("faraxday.mdb") 
    con2.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data source=" & myPath2 & ";" 
    Dim myCommand2 As New System.Data.OleDb.OleDbCommand 
    Dim sql As String 
    myCommand2.Connection = con2 
    con2.Open() 

    'variables' 
    Dim order_date As String 
    Dim coupon_ID As String 
    Dim customer_id As String 
    Dim quantity As String 



    'variables' 

    Try 
     For Each objDR In objDT.Rows 



      order_date = System.DateTime.Now.Date 
      coupon_ID = objDR("ID") 
      quantity = objDR("quantity") 



      myCommand2.CommandText = "INSERT INTO orders(order_date, coupon_id, customer_id, quantity) VALUES (@order_date ,@coupon_ID,@customer_id,@quantity)" 

      myCommand2.Parameters.Add("@order_date", order_date) 
      myCommand2.Parameters.Add("@coupon_ID", coupon_ID) 
      myCommand2.Parameters.Add("@customer_id", custID) 
      myCommand2.Parameters.Add("@quantity", quantity) 


      myCommand2.ExecuteNonQuery() 


     Next 
    Catch ex As Exception 
     objDT = Session("Cart") 
     test.Text = ex.toString() 

    Finally 
     If con2.State = ConnectionState.Open Then 
      con2.Close() 

     End If 
    End Try 
End Function 

Answer 1

避免重复可能会在for循环中添加另一个筛选。

喜欢的东西：

For Each objDR In objDT.Rows 

//Add some filter here 
// "Select Unique ID from Table where Id=@Id" 
// Load to DataSet 
//Check if Exists 

If(dt.Tables[0].Rows.Count > 0) THEN 
//NOT SAVE 
Else 

//Save 

    order_date = System.DateTime.Now.Date 
    coupon_ID = objDR("ID") 
quantity = objDR("quantity") 
myCommand2.CommandText = "INSERT INTO orders(order_date, coupon_id, customer_id, quantity) VALUES (@order_date ,@coupon_ID,@customer_id,@quantity)"    myCommand2.Parameters.Add("@order_date", order_date)    
myCommand2.Parameters.Add("@coupon_ID", coupon_ID)    
myCommand2.Parameters.Add("@customer_id", custID)    
myCommand2.Parameters.Add("@quantity", quantity)    
myCommand2.ExecuteNonQuery() 

END 

Next 

问候