刪除XML節點

Question

我有XML，看起來像

<MeasureSet> 
    <MeasureSetType val_type="name">Variant</MeasureSetType> 
    <Measure> 
     <MeasureType val_type="name">single nucleotide variant</MeasureType> 
     <AttributeSet> 
     <MeasureAttributeType val_type="name">HGVS</MeasureAttributeType> 
     <Attribute>NM_000054.4:c.838dupT</Attribute> 
     </AttributeSet> 
     <Citation> 
     <CitationType val_type="name">general</CitationType> 
     <ID Source="PubMed">10820168</ID> 
     </Citation> 
     <Citation> 
     <CitationType val_type="name">general</CitationType> 
     <ID Source="PubMed" /> 
     </Citation> 
     <Citation> 
     <CitationType val_type="name">general</CitationType> 
     <ID Source="PubMed">9773787</ID> 
     </Citation> 
     <Citation> 
     <CitationType val_type="name">general</CitationType> 
     <ID Source="PubMed">18726898</ID> 
     </Citation> 
     <Citation> 
     <CitationType val_type="name">general</CitationType> 
     <ID Source="PubMed" /> 
     </Citation> 
    </Measure> 
    </MeasureSet> 

我想刪除具有引用/ ID/@來源=「考研」和引文/ ID是引用元素節點空

這僅刪除ID元素，但正確的人

SET @myBlob.modify('delete //Citation/ID[@Source = ''PubMed'' 
     and string-length(string(number(.))) = 0]') 

，這將刪除所有引用元素

SET @myBlob.modify('delete //Citation[ID/@Source = ''PubMed'' 
     and string-length(string(number(.))) = 0]') 

似乎應該有一個簡單的解決方案，我沒有打。有什麼建議麼？謝謝

Answer 1

你的第二個檢查錯誤元素的長度 - 它看着(.)，這裏是Citation元素（因爲它在Citation元素的謂詞中）。改用

SET @myBlob.modify(' 
     delete //Citation[ID/@Source = ''PubMed'' 
         and string-length(string(number(ID[1]))) = 0]') 

，我已經改變.到ID[1]。需要[1]，因爲「'number()' requires a singleton (or empty sequence)」。