使用命名空间提取 XML 标记 [英] Extract XML tag with namespace

问题描述

我需要提取一个 XML 标记值，如下面的代码所示.

I need to extract a XML tag value as in the code below.

设置 serveroutput on宣布lv_xml varchar2(500);xmlstring XMLTYPE;lv_val varchar2(10);开始lv_xml :='<?xml version="1.0" encoding="UTF-8"?><TestMain xmlns="http://www.w3.org/2001/XMLSchema-instance"><testTag1>VAL 1</testTag1><testTag2>VAL 2</testTag2><testTag3>VAL 3</testTag3></TestMain>';xmlstring := XMLTYPE.CREATEXML(lv_xml);选择提取值(值(fd)，'testTag2')进入 lv_valFROM TABLE(XMLSEQUENCE(xmlstring.EXTRACT('TestMain'))) f,表(XMLSEQUENCE(提取(值(f)，'TestMain/testTag2'))) fd;dbms_output.put_line('Val:'||lv_val);例外当其他人然后dbms_output.put_line('错误:'||SQLCODE||' '||SQLERRM);结尾;/

当我运行它时，出现异常ORA-01403: no data found.

When I am running it, I am getting an exception ORA-01403: no data found.

我发现，如果我删除 XML 命名空间 xmlns="http://www.w3.org/2001/XMLSchema-instance"，那么它就可以正常工作.但是，我将从中提取值的 XML 流将采用这种格式(即，它将包含一个命名空间).

I found that, if I remove the XML namespace xmlns="http://www.w3.org/2001/XMLSchema-instance", then it is working fine. But, the XML stream from which I will extract values will be in this format(that is, it will contain a namespace).

有什么办法可以在 xmlns 存在的情况下提取值?

Is there any way to be able extract value with xmlns present?

推荐答案

你在这里:

declare
    lv_xml     varchar2(500);
    xmlstring  XMLTYPE;
    lv_val     varchar2(10);
BEGIN
    lv_xml :=
    '<?xml version="1.0" encoding="UTF-8"?>
    <TestMain xmlns="http://www.w3.org/2001/XMLSchema-instance">
        <testTag1>VAL 1</testTag1>
        <testTag2>VAL 2</testTag2>
        <testTag3>VAL 3</testTag3>
    </TestMain>';

    xmlstring := XMLTYPE.CREATEXML(lv_xml);

    SELECT EXTRACTVALUE(VALUE(fd), '.')
    INTO lv_val
    FROM TABLE(XMLSEQUENCE(xmlstring.EXTRACT('/TestMain', 'xmlns="http://www.w3.org/2001/XMLSchema-instance"'))) f,
        TABLE(XMLSEQUENCE(EXTRACT(VALUE(f), '/TestMain/testTag2', 'xmlns="http://www.w3.org/2001/XMLSchema-instance"'))) fd
    ;

    dbms_output.put_line('Val: '||lv_val);
EXCEPTION
    WHEN OTHERS THEN
       dbms_output.put_line('Error: '||SQLCODE||' '||SQLERRM);
END;
/

为了代码的可读性，你可以在 select 中将特定的内容写成

And for the code readability sake you can write the particular inside select as

SELECT EXTRACTVALUE(xmlstring, '/TestMain/testTag2', 'xmlns="http://www.w3.org/2001/XMLSchema-instance"')
INTO lv_val
FROM dual;

甚至更具可读性(尽管功能上不是 100% 相同)

or even more readable (though functionally not 100% identical)

lv_val := xmlstring.extract('/TestMain/testTag2/text()', 'xmlns="http://www.w3.org/2001/XMLSchema-instance"').getStringVal();

这篇关于使用命名空间提取 XML 标记的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！