Question

我有代码循环遍历数据表并将它们插入到数据库中。第一个循环中的数据插入正常，但它会重复循环的其余部分。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循环中添加另一个过滤。

类似的东西：

 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

此致

循环使用DB（Datatable对象不引用）ASP.NET VB

1 个答案: