ORA-3181:PL/SQL DOM句柄访问不再可用的节点

Question

我正试图从Oracle SQL表中提取数据，当我像下面的例子一样将写入文件放在循环之外时，Oracle SQL表已经工作到了一定程度。但在下面的代码中，当我将对文件的写入放入循环中时，它会出现ORA-3181错误。

我试图在更大范围内做的是，通过向clob写入XML，在每次循环时将其输出到平面文件，从而将XML加载到文件中。

DECLARE -- this version of code works as the write to is outside loop
 l_file    UTL_FILE.FILE_TYPE;
 l_clob    CLOB;
 l_buffer  VARCHAR2(32767);
 l_amount  BINARY_INTEGER := 32767;
 l_pos     INTEGER := 1;
 l_extract_dir               CONSTANT dba_directories.directory_name%TYPE:= 'REPORTS_OUT_DIR';   -- \data2datadownloadd7prdv1prsrepreports  

 l_xmltype XMLTYPE;
 l_domdoc dbms_xmldom.DOMDocument;
 l_root_node dbms_xmldom.DOMNode;     
 l_message_node            dbms_xmldom.DOMNode;
 l_production_element    dbms_xmldom.DOMElement;
 l_production_node       dbms_xmldom.DOMNode;
  -- production XML elements, node, text
 l_prod_element                   dbms_xmldom.DOMElement;     
 l_prod_node         dbms_xmldom.DOMNode;
 l_prod_t_node          dbms_xmldom.DOMNode;
 l_prod_text          dbms_xmldom.DOMText;
-- production XML elements, node, text, node

 CURSOR c_production
 IS SELECT prod.cre_surr_id            as cre_surr_id
         , prod.production_type        as prodCategoryType
    from productions prod            
    where prod.cre_surr_id in (1753959927,1753959929);
 BEGIN 
   UTL_FILE.FCLOSE_ALL;
   l_file := UTL_FILE.fopen(l_extract_dir , 'Sample2.dat', 'w', 32767);
 -- Create an empty XML document
 l_domdoc := dbms_xmldom.newDomDocument;
 -- Create a root node
 l_root_node := dbms_xmldom.makeNode(l_domdoc);
 -- Create a message root node
 l_message_node := dbms_xmldom.appendChild( l_root_node
                                      ,   dbms_xmldom.makeNode(dbms_xmldom.createElement(l_domdoc, 'message' ))
                                     );     
   FOR production_rec in c_production LOOP
     l_production_element := dbms_xmldom.createElement(l_domdoc, 'production' );
     l_production_node    := dbms_xmldom.appendChild(l_message_node,dbms_xmldom.makeNode(l_production_element));  
    -- prodCategoryType
     l_prod_element := dbms_xmldom.createElement(l_domdoc, 'prodCategoryType' );
     l_prod_node   := dbms_xmldom.appendChild(l_production_node,dbms_xmldom.makeNode(l_prod_element));
     l_prod_text    := dbms_xmldom.createTextNode(l_domdoc, production_rec.prodCategoryType );
     l_prod_t_node   := dbms_xmldom.appendChild(l_prod_node,dbms_xmldom.makeNode(l_prod_text));
  END LOOP;
  l_xmltype := dbms_xmldom.getXmlType(l_domdoc);
  dbms_xmldom.freeDocument(l_domdoc);
  l_clob := l_xmltype.getClobVal;   
  DBMS_LOB.read (l_clob, l_amount, l_pos, l_buffer);
  UTL_FILE.put(l_file, l_buffer);
  l_pos := l_pos + l_amount;
  UTL_FILE.fclose(l_file);
END;

当我将写入文件放入循环中时，下面的代码会创建一条错误消息。

错误消息如下。

第1行出现错误ORA-3181:PL/SQL DOM句柄访问不再可用的节点ORA-06512：在"XDB.DBMS_XMLDOM"，第4735行ORA-06512：在"XDB.DBMS_XMLDOM"，第4762行ORA-06512：在第52行

DECLARE -- this version of code DOES not work and creates the ORA-31181 error
 l_file    UTL_FILE.FILE_TYPE;
 l_clob    CLOB;
 l_buffer  VARCHAR2(32767);
 l_amount  BINARY_INTEGER := 32767;
 l_pos     INTEGER := 1;
 l_extract_dir               CONSTANT dba_directories.directory_name%TYPE:= 'REPORTS_OUT_DIR';   -- \data2datadownloadd7prdv1prsrepreports  

 l_xmltype XMLTYPE;
 l_domdoc dbms_xmldom.DOMDocument;
 l_root_node dbms_xmldom.DOMNode;     
 l_message_node            dbms_xmldom.DOMNode;
 l_production_element    dbms_xmldom.DOMElement;
 l_production_node       dbms_xmldom.DOMNode;
  -- production XML elements, node, text
 l_prod_element                   dbms_xmldom.DOMElement;     
 l_prod_node         dbms_xmldom.DOMNode;
 l_prod_t_node          dbms_xmldom.DOMNode;
 l_prod_text          dbms_xmldom.DOMText;
 -- production XML elements, node, text, node

 CURSOR c_production
 IS SELECT prod.cre_surr_id            as cre_surr_id
         , prod.production_type        as prodCategoryType
    from productions prod            
    where prod.cre_surr_id in (1753959927,1753959929);
 BEGIN 
   UTL_FILE.FCLOSE_ALL;
   l_file := UTL_FILE.fopen(l_extract_dir , 'Sample2.dat', 'w', 32767);
  -- Create an empty XML document
  l_domdoc := dbms_xmldom.newDomDocument;
  -- Create a root node
  l_root_node := dbms_xmldom.makeNode(l_domdoc);
  -- Create a message root node
  l_message_node := dbms_xmldom.appendChild( l_root_node
                                      , dbms_xmldom.makeNode(dbms_xmldom.createElement(l_domdoc, 'message' ))
                                     );     

   FOR production_rec in c_production LOOP
     l_production_element := dbms_xmldom.createElement(l_domdoc, 'production' );
     l_production_node    := dbms_xmldom.appendChild(l_message_node,dbms_xmldom.makeNode(l_production_element));  
    -- prodCategoryType
     l_prod_element := dbms_xmldom.createElement(l_domdoc, 'prodCategoryType' );
     l_prod_node   := dbms_xmldom.appendChild(l_production_node,dbms_xmldom.makeNode(l_prod_element));
     l_prod_text    := dbms_xmldom.createTextNode(l_domdoc, production_rec.prodCategoryType );
     l_prod_t_node   := dbms_xmldom.appendChild(l_prod_node,dbms_xmldom.makeNode(l_prod_text));

   l_xmltype := dbms_xmldom.getXmlType(l_domdoc);
   dbms_xmldom.freeDocument(l_domdoc);
   l_clob := l_xmltype.getClobVal;   
   DBMS_LOB.read (l_clob, l_amount, l_pos, l_buffer);
   UTL_FILE.put(l_file, l_buffer);
    l_pos := l_pos + l_amount;

    END LOOP;
   UTL_FILE.fclose(l_file);
 END;

Answer 1

最简单的方法。

begin     
for rec in ( SELECT xmlserialize(content xmlelement("production",
                xmlelement("prodCategoryType",prod.production_type)) as varchar2(4000)) val from productions prod ) loop
dbms_output.put_line(rec.val) ;   
end loop;                                    
end;    

或者在您的代码中，在声明中添加v_temp DBMS_XMLDOM.DOMNODE;，并用temp:= DBMS_XMLDOM.REMOVECHILD(l_message_node,l_production_node); 替换dbms_xmldom.freeDocument(l_domdoc);