sql - 为什么在 SQL Server 中修改 XML 属性时会删除回车符？

Question

在 SQL Server 2014 中，我尝试使用 XML 数据类型的“修改”方法添加一个带有属性(包含回车符)的 XML 元素。回车被删除 - 这是为什么？

例子:

declare @xmldata xml

select 
    @xmldata = '<root><child myattr="carriage returns &#xD;&#xA; are not a problem"></child></root>'

set 
   @xmldata.modify('insert <child>modifying text with carriage returns works&#xD;&#xA;ok</child> after (//child)[1]')

set 
   @xmldata.modify('insert <child myattr="but not&#xD;&#xA;attribute values... why is that?"></child> after (//child)[2]')

select @xmldata

结果:

<root>
  <child myattr="carriage returns &#xD;&#xA; are not a problem" />
  <child>modifying text with carriage returns works
ok</child>
  <child myattr="but not attribute values... why is that?" />
</root>

Answer 1

空白字符可以被解析器规范化。

比照http://www.w3.org/TR/1998/REC-xml-19980210#AVNormalize

虽然您的 XML 是有效的，但具体如何呈现空白取决于实现。如您所见，crlf 已替换为一个空格。

Please note

In general XML works different with Content and Structural/Meta Data

Attribute values are considered structure and data between tags is considered content.

In the design of XML it was never expected that attributes would be displayed on end-user devices, I would suggest you just make another tag for this end user content.