VB.Net OLEDB ExecuteNonQuery INSERT INTO - 对数据库没有影响

Question

这是我的问题：我有下面的代码。如果我调试我的代码并将查询直接复制到 MS Access 中，则查询工作得很好，但如果我从我的应用程序中执行它，则不会对 table 进行任何更改。

请注意，与数据库的连接是正常的，因为我在此之前做了几次 Select 工作得很好。

我可能在做一些愚蠢的事情，但它太大了，我花了很多时间才看到它。

我知道我应该在我的查询中使用参数，我最初是这样做的，但我在我的许多尝试中改变了它，我想这应该不会改变太多。

    Dim cmd As New OleDbCommand
    Dim sQuery As String = String.Empty

    Try
        cmd.CommandText = "DELETE * FROM tbl_Invoices"
        cmd.ExecuteNonQuery()
    Catch ex As Exception
        MsgBox("PrepareInvoicing Delete" & vbCrLf & ErrorToString())
        Exit Sub
    End Try

    'Insert into the Invoice table the fleet info with Usage for the invoicing period selected
    Try
        sQuery = String.Empty
        sQuery = sQuery & "INSERT INTO tbl_Invoices "
        sQuery = sQuery & "SELECT tbl_Fleet.CustomerName AS CustomerName, "
        sQuery = sQuery & "tbl_Fleet.CountryCode AS CountryCode, "
        sQuery = sQuery & "#" & DateSerial(InvoicingYear, InvoicingMonth + 1, 0) & "# AS InvoiceDate, "
        sQuery = sQuery & "tbl_Fleet.Area AS Area, "
        sQuery = sQuery & "tbl_Fleet.Group AS [Group], "
        sQuery = sQuery & "tbl_Fleet.Site_nm AS SiteName, "
        sQuery = sQuery & "tbl_Sites.RCS AS CustomerPO, "
        sQuery = sQuery & "tbl_Fleet.Site_Addr_1 AS SiteAddress1, "
        sQuery = sQuery & "tbl_Fleet.Site_Addr_2 AS SiteAddress2, "
        sQuery = sQuery & "tbl_Fleet.Site_Addr_ZIP AS ZIP, "
        sQuery = sQuery & "tbl_Fleet.Site_Addr_cty AS City, "
        sQuery = sQuery & "tbl_Fleet.model_nm AS ProductDescription, "
        sQuery = sQuery & "tbl_Fleet.product_no AS ProductNumber, "
        sQuery = sQuery & "tbl_Fleet.serial_no AS SerialNumber, "
        sQuery = sQuery & "tbl_Fleet.hostname AS hostname, "
        sQuery = sQuery & "tbl_Fleet.asset_no AS AssetNumber, "
        sQuery = sQuery & "tbl_Fleet.Grid AS Grid, "
        sQuery = sQuery & "tbl_Fleet.ChangeOrderID AS ChangeOrderID, "
        sQuery = sQuery & "tbl_Fleet.install_date AS InstalledDate, "
        sQuery = sQuery & "INT(((tbl_Fleet.install_date - temptbl_CO.ChangeOrderStartDate)/365.25)+1) AS YearInContract, "
        sQuery = sQuery & "(tbl_RM.BlackClicks + tbl_RM.AccentClicks) AS BlackPages, "
        sQuery = sQuery & "(tbl_RM.ColorClicks + tbl_RM.ProfessionalColorClicks) AS ColorPages "
        sQuery = sQuery & "FROM tbl_Fleet, "
        sQuery = sQuery & "tbl_Sites, "
        sQuery = sQuery & "tbl_RM, "
        sQuery = sQuery & "(SELECT DISTINCT tbl_Bases.ProductNumber, tbl_Bases.ChangeOrderID, tbl_Bases.ChangeOrderStartDate FROM tbl_Bases WHERE tbl_Bases.CustomerName = '" & mdlGlobalStuff.SelectedCustomerName & "' AND tbl_Bases.CountryCode = '" & mdlGlobalStuff.SelectedCountryCode & "')  AS temptbl_CO "
        sQuery = sQuery & "WHERE tbl_Fleet.CustomerName = '" & mdlGlobalStuff.SelectedCustomerName & "' "
        sQuery = sQuery & "AND tbl_Fleet.CountryCode = '" & mdlGlobalStuff.SelectedCountryCode & "' "
        sQuery = sQuery & "AND tbl_Fleet.LoadDate = #" & LoadFleetDate & "# "
        sQuery = sQuery & "AND MONTH(tbl_RM.RMDate) = " & Month(LoadUsageDate) & " "
        sQuery = sQuery & "AND YEAR(tbl_RM.RMDate) = " & Year(LoadUsageDate) & " "
        sQuery = sQuery & "AND tbl_Fleet.CustomerName = tbl_Sites.CustomerName "
        sQuery = sQuery & "AND tbl_Fleet.CountryCode = tbl_Sites.CountryCode "
        sQuery = sQuery & "AND tbl_Fleet.Site_nm = tbl_Sites.Site_nm "
        sQuery = sQuery & "AND tbl_Fleet.CustomerName = tbl_RM.CustomerName "
        sQuery = sQuery & "AND tbl_Fleet.CountryCode = tbl_RM.CountryCode  "
        sQuery = sQuery & "AND tbl_Fleet.serial_no = tbl_RM.SerialNumber "
        sQuery = sQuery & "AND tbl_Fleet.product_no = temptbl_CO.ProductNumber "
        sQuery = sQuery & "AND tbl_Fleet.ChangeOrderID = temptbl_CO.ChangeOrderID "
        cmd.CommandText = sQuery
        cmd.ExecuteNonQuery()
        MsgBox("Step 1")
    Catch ex As Exception
        MsgBox("PrepareInvoicing: Invoicing step 1" & vbCrLf & ErrorToString())
        Exit Sub
    End Try

    'Update the "non aging" Bases (if Base.contractYear = 0) in the Invoice table
    Try
        sQuery = String.Empty
        sQuery = sQuery & "UPDATE tbl_Invoices "
        sQuery = sQuery & "INNER JOIN tbl_Bases ON tbl_Bases.ProductNumber  =  tbl_Invoices.ProductNumber "
        sQuery = sQuery & "AND tbl_Bases.ChangeOrderID = tbl_Invoices.ChangeOrderID "
        sQuery = sQuery & "SET tbl_Invoices.Base = tbl_Bases.BasePrice "
        sQuery = sQuery & "WHERE tbl_Bases.CustomerName = '" & mdlGlobalStuff.SelectedCustomerName & "' "
        sQuery = sQuery & "AND tbl_Bases.CountryCode = '" & mdlGlobalStuff.SelectedCountryCode & "' "
        sQuery = sQuery & "AND tbl_Bases.ContractYear = 0 "
        cmd.CommandText = sQuery
        cmd.ExecuteNonQuery()
        MsgBox("Step 2")
    Catch ex As Exception
        MsgBox("PrepareInvoicing: Invoicing step 2" & vbCrLf & ErrorToString())
        Exit Sub
    End Try

    'Update the "aging" Bases (if Base.contractYear <> 0) in the Invoice table
    Try
        sQuery = String.Empty
        sQuery = sQuery & "UPDATE tbl_Invoices "
        sQuery = sQuery & "INNER JOIN tbl_Bases ON tbl_Bases.ProductNumber  =  tbl_Invoices.ProductNumber "
        sQuery = sQuery & "AND tbl_Bases.ChangeOrderID = tbl_Invoices.ChangeOrderID "
        sQuery = sQuery & "AND tbl_Bases.ContractYear =  tbl_Invoices.YearInContract  "
        sQuery = sQuery & "SET tbl_Invoices.Base = tbl_Bases.BasePrice "
        sQuery = sQuery & "WHERE tbl_Bases.CustomerName = '" & mdlGlobalStuff.SelectedCustomerName & "' "
        sQuery = sQuery & "AND tbl_Bases.CountryCode = '" & mdlGlobalStuff.SelectedCountryCode & "' "
        cmd.CommandText = sQuery
        cmd.ExecuteNonQuery()
        MsgBox("Done")
    Catch ex As Exception
        MsgBox("PrepareInvoicing: Invoicing step 3" & vbCrLf & ErrorToString())
        Exit Sub
    End Try

Answer 1

我将继续 post 这是一个答案，因为根据我的经验，它至少有 95% 的可能性适用。

当您添加本地数据文件时，例如MDB 或 ACCDB 文件，对于您的项目，它与所有其他源文件一起被复制到项目文件夹中。该文件是您项目的一部分，而不是您的应用程序的一部分。任何模式更改或默认数据都会添加到该文件，但在测试时运行时不会被触及。

当您构建项目时，该源文件会与您的 EXE 一起复制到输出文件夹。这是您的应用程序在运行时使用的副本。您保存的任何数据都会保存到该工作副本，而不是源文件。

默认情况下，每次构建时都会制作源文件的新副本并覆盖工作副本。这意味着，如果您在调试器中运行您的应用程序，保存一些数据，停止应用程序，更改代码，然后再次运行应用程序，您保存的数据将会消失。

因此，您可能犯的错误与许多错误一样，是您要么在源文件中查找您在运行时间保存的数据，要么在被下一个构建覆盖后的工作副本。这个 "issue" 的解决方案很简单。 Select 在解决方案资源管理器中打开您的数据文件，打开属性 window 并将 Copy to Output Directory 属性设置为 Copy if Newer。这意味着当您构建时，如果源文件较新，工作副本将永远被覆盖，如果您修改了模式或编辑了默认数据，就会出现这种情况。如果您需要刷新您的工作数据库，您只需从输出文件夹中手动删除它或暂时将 Copy to Output Directory 设置回 Copy Always。

您可能想知道为什么他们首先使用多个文件，但这是完全合乎逻辑的，实际上是一件好事。如果您只有一个文件并将其用于测试，那么在部署时会发生什么？您将不得不浪费时间清理那个文件，然后您可能会遗漏一些东西。这样，您只需继续使用您的调试副本进行测试，当您进行发布构建时，您将始终获得一个干净的数据文件。

VB.Net OLEDB ExecuteNonQuery INSERT INTO - 对数据库没有影响

VB.Net OLEDB ExecuteNonQuery INSERT INTO - No effect on Database

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