使用 T-SQL 更新多个 XML 节点 [英] Updating multiple XML nodes using T-SQL

问题描述

可能的重复:
TSQL 2005，XML DML - 一次更新两个值?

假设我有一个包含 XML 列的数据库表.

Say I have a database table with an XML column.

对于每一行，XML 的结构相同(或相似)，但标签的内容不同.

For each row, the XML is structured the same (or similarly) but the content of the tags is different.

结构看起来像这样:

<Parent1>
  <Parent2>
    <Child>
       test 1
    </Child>
  </Parent2>
  <Parent2>
    <Child>
       test 2
    </Child>
  </Parent2>
</Parent1>

我想对结构中的每个子"节点进行一些处理，并用结果更新它们.

I want to do some processing on each 'Child' node in the structure and update them with the results.

例如，我想用something"这个词替换test"这个词.

For example, I want to replace the word 'test' with the word 'something'.

所以我不希望两个子节点最终都包含 'something 1'.

So I don't want both child nodes to end up containing 'something 1'.

相反，我希望第一个子节点包含something 1"，第二个子节点包含something 2".

Rather, I want the first child node to contain 'something 1' and the second child node to contain 'something 2'.

我可以编写以下内容，一次定位一个单个节点:

I could write the following, to target a single node at a time:

DECLARE @replacement NVARCHAR(4000) = 'something 1'
UPDATE MyTable
SET MyXMLField.modify('replace value of (Parent1[1]/Parent2[1]/Child[1]/text())[1] with sql:variable("@replacement")')
WHERE Id = 1

但是是否可以编写一个 T-SQL 语句来处理 多个 节点，与 XPath 匹配，并根据函数的结果单独更新每个节点?

But is it possible to write a T-SQL statement that will process multiple nodes, matched by an XPath, and update each of them individually, according to, say, the result of a function?

推荐答案

你必须循环进行，一次一个节点.

You have to do it in a loop, one node at a time.

declare @MyTable table(Id int, MyXMLField xml)
insert into @MyTable values
(1, '<Parent1>
       <Parent2>
         <Child>test 1</Child>
       </Parent2>
       <Parent2>
         <Child>test 2</Child>
       </Parent2>
     </Parent1>')

declare @replacement nvarchar(4000) = 'something 1'
declare @Parent2Count int
select @Parent2Count = MyXMLField.value('count(/Parent1/Parent2)', 'int')
from @MyTable
where Id = 1

declare @Node int
set @Node = 1

while @Node <= @Parent2Count
begin
  update @MyTable set
    MyXMLField.modify('replace value of 
                          (/Parent1/Parent2[sql:variable("@Node")]/Child/text())[1] 
                          with sql:variable("@replacement")')
  where Id = 1    

  set @Node = @Node + 1
end

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