Question

我有一个类似于以下功能，返回大块xml（在生产环境中），在应用程序的各个阶段，我们只需要从中检索一些元素或仅检索一些属性。

create function testrig.fxConfigurations(@context varchar(300)) returns xml as 
begin
return (select 
'<configurations realm="configuration">
    <context name="apera">
        <backends>
            <backend name="Hades">
                <os>HP Unix</os>
                <ip>nnn.nnn.nnn</ip>
                <db vender="Oracle" version="11g">
                    <netconnect>Data Source= (DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = hades)(PORT = 1521)(RECV_BUF_SIZE=1048576))(CONNECT_DATA =(SERVER = DEDICATED)(SERVICE_NAME = baan)));Password=********;User ID=ItsMe;" providerName="Oracle.DataAccess.Client"
                    </netconnect>
                </db>
            </backend>
            <backend name="Athena">
                <os>HP Unix</os>
                <ip>nnn.nnn.nnn</ip>
                <db vender="Oracle" version="11g">
                    <netconnect>Data Source= (DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = hades)(PORT = 1521)(RECV_BUF_SIZE=1048576))(CONNECT_DATA =(SERVER = DEDICATED)(SERVICE_NAME = baan)));Password=********;User ID=ItsMe;" providerName="Oracle.DataAccess.Client"
                    </netconnect>
                </db>
            </backend>
        </backends>
    </context>
</configurations>
')

end 
go

如何仅检索属性名称，即“Hades＆＃39;”，“Athena＆＃39;像这样使用xQuery

select (testrig.fxConfigurations(null).query('configurations/context[@name="apera"]/backends').query('/descendant-or-self::*'))

Answer 1

如果要连接backend/@name属性的所有值（ala GROUP_CONCAT）：

select testrig.fxConfigurations(null)
   .query('data(configurations/context[@name="apera"]/backends/backend/@name)')

如果您需要单独使用这些属性，则可能需要使用nodes来提取它们：

WITH cteXml AS
(
    SELECT testrig.fxConfigurations(null)
           .query('configurations/context[@name="apera"]') as context
)
SELECT Nodes.node.value('@name', 'varchar(50)') AS backEndName
FROM cteXml
    CROSS APPLY cteXml.context.nodes('//backends/backend') as Nodes(node);

Fiddle here

如何仅使用xQuery检索属性

1 个答案: