如何更新没有根元素的clob oracle中的xml元素

Question

我想更新 oracle 的 clob 列中的特定 xml 元素值。 xml如下

<TraceOn>NO</TraceOn>
<isDateTimePopulated>NO</isDateTimePopulated>
<serviceProvider>LWS</serviceProvider>
<AutomatedRetry>YES</AutomatedRetry>
<retryDateTime>2018-08-29-18.15.07</retryDateTime>

此数据没有根元素，我尝试通过以下查询更新 retryDateTime 但它不起作用。

update READ_DATA p1 
set p1.bo_data = to_clob(updatexml(xmltype(p1.bo_data),
                 '/retryDateTime/text()','2018-08-29-18.15.07') )
 where INIT_MSRMT_DATA_ID='57610034614521';

Answer 1

1) 通过添加根节点使 xml 格式良好。

2) 使用 xquery 更新节点（不推荐使用 updatexml）

3) 只返回根的孩子

select xmlserialize(content xmlquery( 'copy $tmp := $xml_data modify 
    (for $i in $tmp/root/retryDateTime
               return replace value of node $i with $value)
               return $tmp/root/*'
passing  xmltype('<root>'||'<TraceOn>NO</TraceOn>
<isDateTimePopulated>NO</isDateTimePopulated>
<serviceProvider>LWS</serviceProvider>
<AutomatedRetry>YES</AutomatedRetry>
<retryDateTime>2018-08-29-18.15.07</retryDateTime>'||'</root>') as "xml_data", 'new node value' as "value" returning content) as clob indent size = 2)  from dual;

有用的例子https://docs.oracle.com/database/121/ADXDB/app_depr_upd.htm#ADXDB6044

Answer 2

大多数 XML-Function 需要在 SQL 而不是 plsql 中使用。

这里是一步一步的：

DECLARE
    myClob   VARCHAR2 (4000) := '<TraceOn>NO</TraceOn>
<isDateTimePopulated>NO</isDateTimePopulated>
<serviceProvider>LWS</serviceProvider>
<AutomatedRetry>YES</AutomatedRetry>
<retryDateTime>2018-08-29-18.15.07</retryDateTime>';

    myXml    XMLTYPE;
    tmp      VARCHAR2 (4000);
    tmpDate  Date;
BEGIN
    DBMS_OUTPUT.put_line (' - - - build valid xml, by adding a root - - - ');
    myXml := XMLTYPE.CREATEXML ('<faketag>' || myClob || '</faketag>');

    DBMS_OUTPUT.put_line (myXml.getClobVal ());

    DBMS_OUTPUT.put_line (' - - - extract the desired tag - - - ');

    SELECT EXTRACTVALUE (myXml, '/faketag/retryDateTime') INTO tmp FROM DUAL; -- EXTRACTVALUE is ONLY allowed in SQL not PL/SQL! We need a select-into
    DBMS_OUTPUT.put_line (tmp);
    DBMS_OUTPUT.put_line (' - - - Extract the date to check the value and work with it - - - ');

    tmpDate := to_date(tmp,'yyyy-mm-dd-HH24.MI.SS');
    dbms_output.put_line('MyDate: ' || tmpDate); 

    dbms_output.put_line(' - - - update our xml - - - ');
    select updateXML(myXml, '/faketag/retryDateTime', '2017-01-01-13.59.59') into myXml from dual; -- updateXML is ONLY allowed in SQL not PL/SQL! We need a select-into
    DBMS_OUTPUT.put_line (myXml.getClobVal ());

    dbms_output.put_line(' - - - now it''s you turn ;) - - - '); 
END;