是否可以在PL/SQL中對精確行進行異常處理？

Question

錯誤在確定的行中時是否有可能發生異常？

例如，這是我的代碼片段：

l_XMLvalue := l_xmltype.extract('/SHOW_SHIPMENT_005/DATAAREA/SHOW_SHIPMENT/SHIPMENT/SHIPITEM/QUANTITY/VALUE/text()').getStringVal(); 
dbms_output.put_line('QUANTITY: '||l_XMLvalue); 
l_XMLdocument_id := l_xmltype.extract('/SHOW_SHIPMENT_005/DATAAREA/SHOW_SHIPMENT/SHIPMENT/SHIPITEM/DOCUMNTREF/DOCUMENTID/text()').getStringVal(); 
dbms_output.put_line('DOCUMENT ID:' ||l_XMLdocument_id); 
l_XMLdoc_release := l_xmltype.extract('/SHOW_SHIPMENT_005/DATAAREA/SHOW_SHIPMENT/SHIPMENT/SHIPITEM/DOCUMNTREF/USERAREA/DOCUMENTRELEASE/text()').getStringVal(); 
dbms_output.put_line('DOCUMENT RELEASE:' ||l_XMLdoc_release); 
l_XMLlinenum := l_xmltype.extract('/SHOW_SHIPMENT_005/DATAAREA/SHOW_SHIPMENT/SHIPMENT/SHIPITEM/DOCUMNTREF/LINENUM/text()').getStringVal(); 
dbms_output.put_line('LINE NUMBER:' ||l_XMLlinenum); 
l_XMLsch_lnum := l_xmltype.extract('/SHOW_SHIPMENT_005/DATAAREA/SHOW_SHIPMENT/SHIPMENT/SHIPITEM/DOCUMNTREF/SCHLINENUM/text()').getStringVal(); 
dbms_output.put_line('SCHIPMENT LINE NUMBER:' ||l_XMLsch_lnum); 

當函數提取正在試圖獲取價值，會有NULL，該程序將停止。這是可能的例外：

WHEN SELF_IS_NULL THEN 
dbms_output.put_line('There is a problem with empty values in XML file'); 

這是我想做的事情是檢查在哪一行發生錯誤，並寫異常其準確值是錯誤。

Answer 1

嘗試創建函數extract函數的包裝函數，並確定一個EXCEPTION SELF_IS_NULL並使用RAISE SELF_IS_NULL;如果它返回NULL。

dbms_output.put_line(SQLERRM||chr(10)||dbms_utility.format_error_backtrace);

請把這個在您的異常塊。它打印從它起源（線NO）

Answer 2

一種方式來完成這個堆棧跟蹤是使用檢查點變量，類似以下內容：

BEGIN 
    strXMLelement := '/SHOW_SHIPMENT_005/DATAAREA/SHOW_SHIPMENT/SHIPMENT/SHIPITEM/QUANTITY/VALUE/text()'; 
    l_XMLvalue := l_xmltype.extract(strXMLelement).getStringVal(); 
    dbms_output.put_line('QUANTITY: '||l_XMLvalue); 

    strXMLelement := '/SHOW_SHIPMENT_005/DATAAREA/SHOW_SHIPMENT/SHIPMENT/SHIPITEM/DOCUMNTREF/DOCUMENTID/text()'; 
    l_XMLdocument_id := l_xmltype.extract(strXMLelement).getStringVal(); 
    dbms_output.put_line('DOCUMENT ID:' ||l_XMLdocument_id); 

    strXMLelement := '/SHOW_SHIPMENT_005/DATAAREA/SHOW_SHIPMENT/SHIPMENT/SHIPITEM/DOCUMNTREF/USERAREA/DOCUMENTRELEASE/text()'; 
    l_XMLdoc_release := l_xmltype.extract(strXMLelement).getStringVal(); 
    dbms_output.put_line('DOCUMENT RELEASE:' ||l_XMLdoc_release); 

    strXMLelement := '/SHOW_SHIPMENT_005/DATAAREA/SHOW_SHIPMENT/SHIPMENT/SHIPITEM/DOCUMNTREF/LINENUM/text()'; 
    l_XMLlinenum := l_xmltype.extract(strXMLelement).getStringVal(); 
    dbms_output.put_line('LINE NUMBER:' ||l_XMLlinenum); 

    strXMLelement := '/SHOW_SHIPMENT_005/DATAAREA/SHOW_SHIPMENT/SHIPMENT/SHIPITEM/DOCUMNTREF/SCHLINENUM/text()'; 
    l_XMLsch_lnum := l_xmltype.extract(strXMLelement).getStringVal(); 
    dbms_output.put_line('SCHIPMENT LINE NUMBER:' ||l_XMLsch_lnum); 
EXCEPTION 
    WHEN SELF_IS_NULL THEN 
    DBMS_OUTPUT.PUT_LINE('Error extracting ' || strXMLelement || ' : ' || 
         'SQLCODE=' || SQLCODE || ' SQLERRM=' || SQLERRM); 
END; 

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