SQL Server - Storing linebreaks in XML data type

问题:

Is it possible to store non-alphanumeric characters (more specifically line break characters) in a XML data type?

The code below illustrates my problem:

declare @a xml
declare @b nvarchar(max)

set @b = '<Entry Attrib="1'+CHAR(13)+'2" />'

print @b

set @a=convert(xml,@b,1)

set @b=convert(nvarchar, @a,1)

print @b

The output is:

<Entry Attrib="1
2" />
<Entry Attrib="1 2"/>

Is there any way I could keep the line break intact?

My actual problem is to store the value in a table (rather than a local variable), so maybe there's some setting for the corresponding XML column in my table that would do the job?

回答1:

It would not be possible. The XML Data type is stored as an XML DOM Tree, not a string.

You would have to store it as a varchar instead if you want to keep whitespace.

回答2:

My answer in the XSLT context should apply here:

XML parsed entities are often stored in computer files which, for editing convenience, are organized into lines. These lines are typically separated by some combination of the characters carriage-return (#xD) and line-feed (#xA).

So this might be what you are looking for:

set @b = '<Entry Attrib="1&#xA;2" />'

回答3:

White space inside of an XML tag is not considered significant according to the XML specification, and will not be preserved. White space outside of the element will however:

declare @a xml
declare @b nvarchar(max)

set @b = '<Entry Attrib="12"> fo'+CHAR(13)+'o</Entry>'
print @b
set @a=convert(xml,@b,1)
set @b=convert(nvarchar(max), @a,1)
print @b

will output:

<Entry Attrib="12"> fo
o</Entry>
<Entry Attrib="12"> fo
o</Entry>