vb.net的SQL Union查詢錯誤

Question

該代碼在很長一段時間內一直有效，直到有人在SQL數據庫中添加了導致Web程序崩潰的新名稱（SE01）。 網絡錯誤表明

System.InvalidCastException: Conversion from string "SE01" to type 'Integer'
is not valid.

以及其他SQL Union查詢錯誤，

SELECT Substring([Name],@lenSrv, 8) as Name 
FROM [dbo].[ServerOwners] 
where [Name] like @Srv 
and Name not like '%j%' 
union 
SELECT Substring([Server],@lenSrv, 8) as Name 
FROM [dbo].[AuditLog] 
where log='delete' 
and [DATE] > (GETDATE() - 60) 
and [SERVER] like @Srv 
and Server not like '%j%' 
order by [name]

代碼工作是使用查詢來通過數據庫查找下一個可用名稱，例如，數據庫中的現有服務器名稱為UXVP001，代碼將找到可用的免費名稱為UXVP002。 現在有人在SQL數據庫中添加了UXVPSE01，這似乎導致讀取查詢崩潰。 我希望它被接受/忽略新名稱而不會出現錯誤。

這是在數據庫中搜索的簡短vb代碼，

srv = "UXPV"
sqlAddOn =  "and Name not like '%j%'"
sqlAddOnAudit = "and Server not like '%j%'"

        "Logic to find next available name"
        "1. select the numbers to the right of the characters"
        "2.  loop all values and find first missing number"
        Dim sqlConn As New System.Data.SqlClient.SqlConnection((ConfigurationManager.ConnectionStrings("SOCT").ConnectionString))
        Dim strSql As String = "SELECT  Substring([Name],@lenSrv, 8) as Name  FROM [dbo].[ServerOwners] where [Name] like @Srv " & sqlAddOn
        strSql &= " union "
        strSql &= "SELECT  Substring([Server],@lenSrv, 8) as Name FROM [dbo].[AuditLog] where log='delete' and [DATE] > (GETDATE() - 60) and [SERVER] like @Srv " & sqlAddOnAudit
        strSql &= " order by [name]"
        Dim cmd As New System.Data.SqlClient.SqlCommand(strSql, sqlConn)
        Dim dr As System.Data.SqlClient.SqlDataReader

        LabelError.Text = ""
        Dim x As Integer = 1
        Dim y As Integer = 1
        Dim foundYet As Boolean = False
        Try
            sqlConn.Open()
            cmd.Parameters.AddWithValue("@lenSrv", srv.Length + 1)
            cmd.Parameters.AddWithValue("@Srv", srv & "%")

            dr = cmd.ExecuteReader()

            While dr.Read() And foundYet = False
            LabelError.Text = LabelError.Text & dr("Name") & " | "
            y = CType(dr("Name"), Integer)
            If x = y Then
                "keep going"
                x = x + 1
            Else
                "you found first available number"
                foundYet = True
            End If
        End While

        dr.Close()
        cmd.Dispose()
    Catch ex As Exception
        hide()
        PanelError.Visible = True
        LabelError.Text = ex.ToString() & "<hr/>" & strSql
    Finally
        sqlConn.Dispose()

    End Try

    "make sure leading zeros are present"
    " 000"
    Dim fmt As String = "00#"
    tbAdd_ServerName.Text = srv & x.ToString(fmt)
    tbAdd_ServerName.Enabled = False

    tbAdd_TM.SelectedValue = "*"

Answer 1

當然這是行不通的。 您將一切都放在UXPV的右邊，然后將該值當作數字對待。 但是，對於一條記錄，您將不再有該值的數字。

因此，您需要做的是擺脫不良記錄並更改用戶界面，以便將來無法添加數據類型。 或者，您需要修復代碼以去除所有字母字符。

Answer 2

我意識到我要做的就是添加這樣的代碼來忽略“ SE”，

sqlAddOn = "and Name not like '%j%' and Name not like '%se%'"
sqlAddOnAudit = "and Server not like '%j%' and Server not like '%se%'"

現在，它開始工作並返回到它應該是的搜索方式。