从特定节点循环 XML [英] Looping XML from a specific node

问题描述

我有一个 XML 文件，比如说

I have an XML File, say

<?xml version="1.0" encoding="UTF-8"?>
<sqldiff version="1.0">
    <diff>
        <version>1.0.0</version>
        <sql>
            CODE HERE
        </sql>
    </diff>

    <diff>
        <version>1.0.1</version>
        <sql>
            CODE HERE
        </sql>
    </diff>
</sqldiff>

我正在存储上次执行的差异的版本(在本例中为 1.0.1).我不想在应用程序每次运行时都遍历整个 XML 文件，而是检查是否有任何新的差异(在这种情况下，我可以从上次差异中获取版本).

I am storing the version of the last diff that was executed (In this case 1.0.1). I don't want to loop through the entire XML file every time the application runs, instead, just checks if any new diffs (in this case I can get the version from the last diff).

我的问题是，我不想遍历整个 XML 来比较版本，以了解跳过哪些和执行哪些.

My problem is that, I don't want to loop through the entire XML to comparing versions, to know which ones to skip and which ones to execute.

目前，我正在遍历所有差异并比较版本，直到它获得更新的版本，它才会执行该版本，然后存储最后执行的差异.这是我的代码:

Currently, am looping through all diffs and comparing the versions, untill it gets a newer version, it executes that, then stores the last diff executed. Here is my code:

        Dim BaseVersion = New Version(GetLastVersion()) 'Eg. returns 1.0.2

        Dim xmlDoc As New XmlDocument()
        xmlDoc.Load("D:\sqldiff.xml")
        Dim nodes As XmlNodeList = xmlDoc.DocumentElement.SelectNodes("/sqldiff/diff")
        Dim pID As String = "", pCode As String = ""
        For Each node As XmlNode In nodes
            pID = node.SelectSingleNode("version").InnerText
            pCode = node.SelectSingleNode("sql").InnerText

            'Checks if pID>BaseVersion Then Executes code and store current pID
            'Else Continue
        Next

推荐答案

在寻找了一段时间并没有找到任何与我所寻找的类似的解决方案后，我尝试了几种方法，最终得到了解决.此解决方案 作者 dbasnett 对我解决这个问题很有帮助.

After Looking for a while and not finding any similar solutions to what I was looking for I tried a couple of methods and finally got it working. This Solution by dbasnett was instrumental to me fixing this problem.

首先我得到sqldiff.xml文件

First I get the sqldiff.xml file

Dim xe As System.Xml.Linq.XElement
xe = XElement.Load(IO.Path.Combine(yourpath, "sqldiff.xml"))

接下来我得到最后一个元素(感谢 dbasnett)

Next I get the Last element (Thanks to dbasnett)

Dim lastVersEL As XElement = xe...<version>.LastOrDefault

最后，我使用 lastVersEL 并将其与原始问题中的 baseVersion 进行比较，如果 lastVersEL 更大，则意味着有新的添加diffs，我使用下面的代码来获取传递版本的XElement

Lastly, I use lastVersEL and compare it to baseVersion from the Original Question, and if lastVersEL is greater, it means there are new diffs added, and the I use the code below to get the XElement of the passed version

Dim lastExecutedEL As XElement = (From c In xe...<version> Where c.Value = baseVersion Select c).SingleOrDefault()

并获取索引(我正在寻找的解决方案)

And To get the index (THE SOLUTION I WAS LOOKING FOR)

Dim index As Integer = xe...<version>.Nodes.ToArray.ToList.IndexOf(lastExecutedEL.FirstNode)

然后我按照下面的代码继续循环并执行差异

And then I proceeded to loop and execute the diffs as per the code below

       If lastVersEL > baseVersion Then
           Dim lastExecutedEL As XElement = (From c In xe...<version> Where c.Value = baseVersion Select c).SingleOrDefault()
           Dim index As Integer = xe...<version>.Nodes.ToArray.ToList.IndexOf(lastExecutedEL.FirstNode)

           For i As Integer = index To xe...<version>.Nodes.Count
             'Executes the SQL stored in the Elements by gettings the value as below
             'elements(i).Parent.<sql>.Value.Trim

           Next

        End If

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