按树级别解析分层自连接表？

发布于 2024-09-29 18:53:37 字数 327 浏览 3 评论 0原文

如您所见，我有一个自引用类别表：
alt text

我想解析此表以找出每个类别的树级别。例如，如果根节点级别为 0，则 CPU、硬盘、VGA 和 RAM 处于级别 1，依此类推。我该怎么办？
我创建了一个字典来放置每个类别 ID 及其级别：

Dictionary<int, int> dic = new Dictionary<int, int>();

键是 CategoryId，值是级别。请帮我如何填写字典？

原文

I have a self referential category table as you see:
alt text

I want to parse this table to find out tree level for each category. for example if root node level is 0 then CPU and Hard Drive and VGA and RAM are in level 1 and so on. how can I handle that?

I created a dictionary to put each category ID and its Level:

Dictionary<int, int> dic = new Dictionary<int, int>();

the Key is CategoryId and Value is Level.
please help me how can I Fill the Dictionary?

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自此以后，行同陌路 2024-10-06 18:53:37

您无法在单个 LINQ 查询中轻松完成此操作。你应该使用递归。使用 C# 编写递归函数或在数据库中使用递归 CTE。

对于C#解决方案：

IEnumerable<KeyValuePair<int, int>> GetChildren(int id, int childLevel)
{
    foreach (var row in rows.Where(row => row.ParentID == id && row.ID != id))
    {
        yield return new KeyValuePair<int, int>(row.ID, childLevel);
        foreach (var x in GetChildren(row.ID, childLevel + 1))
        {
            yield return x;
        }
    }
}

调用如下：

GetChildren(0, 0);

You can't do this easily in a single LINQ query. You should use recursion. Either write a recursive function in C# or use a recursive CTE in the database.

For the C# solution:

IEnumerable<KeyValuePair<int, int>> GetChildren(int id, int childLevel)
{
    foreach (var row in rows.Where(row => row.ParentID == id && row.ID != id))
    {
        yield return new KeyValuePair<int, int>(row.ID, childLevel);
        foreach (var x in GetChildren(row.ID, childLevel + 1))
        {
            yield return x;
        }
    }
}

Call as follows: