SQL XQuery；更新类型化 XML 中的属性

Question

我正在尝试更新类型化 XML 中的属性。我过去通过在非类型化对象中构建 XML 然后将其设置为类型化对象来完成此操作（因此避免了这个问题），但我想知道如何直接修改类型化数据。

我的架构是：

if exists (select [xml_collection_id]
           from   sys.[xml_schema_collections] as [xsc]
           where  [xsc].name = 'xsc_test_stack'
                  and [xsc].[schema_id] = schema_id(N'chamomile'))
  drop xml schema collection [chamomile].[xsc_test_stack];

go

create xml schema collection [chamomile].[xsc_test_stack] as N'<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:chamomile="https://github.com/KELightsey/chamomile" targetNamespace="https://github.com/KELightsey/chamomile">
  <xsd:element name="test_stack">
    <xsd:complexType>
      <xsd:sequence>
        <xsd:element name="description" type="xsd:string" minOccurs="1" maxOccurs="1" />
        <xsd:element name="test_stack_detail" type="chamomile:any_complex_type" minOccurs="0" maxOccurs="unbounded" />
        <xsd:element name="test" type="chamomile:any_complex_type" minOccurs="0" maxOccurs="unbounded" />
      </xsd:sequence>
      <xsd:attribute name="name" type="xsd:string" use="required" />
      <xsd:attribute name="test_count" type="xsd:int" use="required" />
      <xsd:attribute name="pass_count" type="xsd:int" use="required" />
      <xsd:attribute name="timestamp" type="xsd:dateTime" use="required" />
     <xsd:anyAttribute processContents="lax" />
    </xsd:complexType>
  </xsd:element>

    <xsd:complexType name="any_complex_type">
        <xsd:complexContent>
            <xsd:restriction base="xsd:anyType">
                <xsd:sequence>
                    <xsd:any minOccurs="0" maxOccurs="unbounded" processContents="lax"/>
                </xsd:sequence>
                <xsd:anyAttribute processContents="lax" />
            </xsd:restriction>
        </xsd:complexContent>
    </xsd:complexType>
</xsd:schema>';

go 

我构建的结构类型示例如下：

declare @test [xml]([chamomile].[xsc_test_stack]) = N'
     <chamomile:test_stack xmlns:chamomile="https://github.com/KELightsey/chamomile" name="[chamomile].[person_test].[get_age]" test_count="2" pass_count="2" timestamp="2018-06-24T15:50:19.3466667">
       <description>This test stack consists of tests which validate the functionality of the age calculation for a person.</description>
     </chamomile:test_stack>';
go

declare @test [xml]([chamomile].[xsc_test_stack]) = N'
     <chamomile:test_stack xmlns:chamomile="https://github.com/KELightsey/chamomile" name="[chamomile].[person_test].[get_age]" test_count="2" pass_count="2" timestamp="2018-06-24T15:50:19.3466667">
       <description>This test stack consists of tests which validate the functionality of the age calculation for a person.</description>
       <test_stack_detail>
          <any_valid_xml_goes_here />
       </test_stack_detail>
     </chamomile:test_stack>';
go

我尝试过的是：

set @test_stack.modify(N'replace value of (//@test_count)[1] with sql:variable("@count")');

返回：Msg 9306, Level 16, State 1, Line 28 XQuery [modify()]: 'replace value of' 的目标不能是联合类型，找到 '(attribute(test_count,xs:int) | attribute(test_count,xs:anySimpleType)) ?'。

set @test_stack.modify(N'declare namespace chamomile="https://github.com/KELightsey/chamomile"; 
    replace value of (chamomile:test_stack/@test_count)[1] with sql:variable("@count")');

返回：Msg 9306, Level 16, State 1, Line 25 XQuery [modify()]: 'replace value of' 的目标不能是联合类型，找到 '(attribute(test_count,xs:int) | attribute(test_count,xs:anySimpleType)) ?'。

我花了几个小时在 Google 上挖掘这个。无类型 XML 的示例有很多很多，而有类型 XML 的一些示例仍然会抛出相同的异常。

我会很感激一些见解。

谢谢， 凯瑟琳

Answer 1

我必须承认，我也没有找到任何直接的方法。似乎是一个错误，至少我认为这没有任何意义。解决方法是一个简单的转换，但这与您在初始行中描述的解决方法非常接近：

declare @test [xml]([chamomile].[xsc_test_stack]) = 
N'<chamomile:test_stack xmlns:chamomile="https://github.com/KELightsey/chamomile" name="[chamomile].[person_test].[get_age]" test_count="2" pass_count="2" timestamp="2018-06-24T15:50:19.3466667">
       <description>This test stack consists of tests which validate the functionality of the age calculation for a person.</description>
     </chamomile:test_stack>';

DECLARE @cnt INT=99;

DECLARE @intermediate XML=CAST(@test AS XML); --magic happens here
SET @intermediate.modify('declare namespace chamomile="https://github.com/KELightsey/chamomile"; 
                          replace value of (chamomile:test_stack/@test_count)[1] with sql:variable("@cnt")');

SET @test=@intermediate; --re-assign to typed XML

SELECT @test;