Question

我正在从SQL数据库中读取并根据我检查的字段，我需要更新同一个表中的其他字段。我循环遍历数据集并尝试在循环时发回UPDATE。它在我的TEST表上工作但不适用于我的生产表。当我执行＆＃34; ExecuteNonQuery＆＃34;命令，我得到超时过期错误。如果我实际关闭第一个连接，然后调用ExecuteNonQuery，它会立即运行。

这是代码......

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        Dim sqlConn As New SqlConnection
        Dim sqlComm As New SqlCommand
        Dim sqlDR As SqlDataReader




        sqlConn.ConnectionString = "Data Source=10.2.0.87;Initial Catalog=Inbound_Orders_DB;User ID=xxxxx;Password=xxxxxx;"
        sqlConn.Open()
        sqlComm.CommandText = "SELECT * FROM RH_Orders  where Order_DateTime is NULL ORDER by Order_Date DESC"
        sqlComm.Connection = sqlConn

        sqlDR = sqlComm.ExecuteReader

        If sqlDR.HasRows Then
            While sqlDR.Read
                If Trim(sqlDR("Order_Date")) <> "" Then
                    Dim order_Date As String = Trim(sqlDR("Order_Date"))
                    Dim order_DateTime As String = ""
                    If Len(order_Date) = 14 Then
                        order_DateTime = order_Date.Substring(0, 4) & "-" & order_Date.Substring(4, 2) & "-" & order_Date.Substring(6, 2) & " "
                        order_DateTime = order_DateTime & order_Date.Substring(8, 2) & ":" & order_Date.Substring(10, 2) & ":" & order_Date.Substring(12, 2)
                        Dim myId As String = sqlDR("ID")

                        Dim sqlConn2 As New SqlConnection
                        Dim sqlComm2 As New SqlCommand

                        sqlConn2.ConnectionString = "Data Source=10.2.0.87;Initial Catalog=Inbound_Orders_DB;User ID=xxxx;Password=xxxx;"
                        sqlConn2.Open()

                        sqlComm2.CommandText = "UPDATE [RH_Orders] SET order_DateTime = '" & order_DateTime & "' WHERE ID=" & myId
                        sqlComm2.Connection = sqlConn2

                        sqlComm2.ExecuteNonQuery()
                        sqlConn2.Close()

                    End If
                End If
            End While

        End If


    End Sub
End Class

Answer 1

使用参数化查询并且不要连接字符串，然后使用SqlParameter和SqlDbType.Datetime并分配实际DateTime而不是格式化字符串。

但也许在这里用DataTable填充SqlDataAdapter.Fill(table)，循环表Rows，更改每个DataRow并使用{{}会更有效率1}}在循环后发送一批中的所有更改。不需要SqlDataAdapter.Update(table)循环。

例如（未经测试）：

SqlDataReader

旁注：而不是建立一个新字符串＆＃34; 2017-01-31＆＃34;来自＆＃34; 20170131＆＃34;你也可以使用Using con = New SqlConnection("Data Source=10.2.0.87;Initial Catalog=Inbound_Orders_DB;User ID=xxxxx;Password=xxxxxx;") Using da = New SqlDataAdapter("SELECT * FROM RH_Orders where Order_DateTime is NULL ORDER by Order_Date DESC", con) da.UpdateCommand = New SqlCommand("UPDATE RH_Orders SET order_DateTime = @order_DateTime WHERE ID = @Id", con) da.UpdateCommand.Parameters.Add("@order_DateTime", SqlDbType.DateTime).SourceColumn = "order_DateTime" Dim table = New DataTable() da.Fill(table) For Each row As DataRow In table.Rows Dim orderDate = row.Field(Of String)("Order_Date") Dim orderDateTime As DateTime If DateTime.TryParse(orderDate.Substring(0, 4) & "-" & orderDate.Substring(4, 2) & "-" & orderDate.Substring(6, 2), orderDateTime) Then row.SetField("order_DateTime", orderDateTime) End If Next da.Update(table) End Using End Using：

DateTime.TryParseExact

VB.NET在DataReader循环中更新相同的表

1 个答案: