Oracle 存储过程中输入参数变量的标识符无效

Question

我正在尝试创建一个存储过程，该过程将从视图中获取所有列并在 CLOB 上为其生成 XML 数据。

CREATE OR REPLACE PROCEDURE PaGenerarServicioXML(vIdViaje IN NUMBER, vIDCliente IN varchar)
IS
ServicioXML CLOB;
BEGIN

  SELECT DBMS_XMLGEN.GETXML (q'!
       SELECT *
      FROM VwServicio VwS
      WHERE VwS.Identificador_Viaje = vIdViaje 
      AND VwS.Identificador_Cliente = vIdCliente
      !')
    INTO ServicioXML
    FROM DUAL;
    SYS.DBMS_OUTPUT.PUT_LINE(ServicioXML);
END;

EXECUTE PaGenerarServicioXML(2,'304560326')

存储过程保存正确。

当我执行这个存储过程时，会抛出以下错误：

ORA-19202: Error occurred in XML processing
ORA-00904: "VIDCLIENTE": invalid identifier ORA-06512: at "SYS.DBMS_XMLGEN", line 176
ORA-06512: at "SYS.DBMS_XMLGEN", line 7
ORA-06512: at "SYS.DBMS_XMLGEN", line 164
ORA-06512: at line 1
ORA-06512: at "SQL_MBFTRUKIWLGITBRTRBBHFHTSA.PAGENERARSERVICIOXML", line 6
ORA-06512: at line 1
ORA-06512: at "SYS.DBMS_SQL", line 1721

如果我删除 WHERE 子句中的 AND 语句，错误将更改为未将 VIDVIAJE 标识为有效。为什么不接受我刚刚创建的输入变量？

在VwServicio 视图中，Identificador_Viaje 是一个INT 数据类型，而Identificador_Cliente 是一个VARCHAR，所以我真的不明白问题出在哪里。

Answer 1

您的查询是一个字符串，DBMS_XMLGEN 在执行内部查询时对外部上下文一无所知。要将参数传递给它，您需要使用此函数签名：

DBMS_XMLGEN.GETXML (
   ctx          IN ctxHandle,
   dtdOrSchema  IN number := NONE)
 RETURN CLOB;

然后从通用游标创建上下文并在此处传递参数：

dbms_xmlgen.newcontext(cursor(
  SELECT *
  FROM VwServicio VwS
  WHERE VwS.Identificador_Viaje = vIdViaje 
    AND VwS.Identificador_Cliente = vIdCliente
))

把它们放在一起，你会得到这样的东西：

create table t
as
select level - 1 as id
from dual
connect by level < 3

create table t_child
as
select mod(level, 6) as id
  , level as child_id
from dual
connect by level < 18

create function f_get_children_xml(
  p_id in int
) return clob
is
  l_cur sys_refcursor;
begin
  open l_cur for
    select *
    from t_child
    where t_child.id = p_id
  ;
  return dbms_xmlgen.getxml(
    ctx => dbms_xmlgen.newcontext(queryString => l_cur)
  );
end;
/

✓

select f_get_children_xml(id)
from t

F_GET_CHILDREN_XML(ID)
<?xml version="1.0"?> <ROWSET> <ROW> <ID>0</ID> <CHILD_ID>6</CHILD_ID> </ROW> <ROW> <ID>0</ID> <CHILD_ID>12</CHILD_ID> </ROW> </ROWSET>
<?xml version="1.0"?> <ROWSET> <ROW> <ID>1</ID> <CHILD_ID>1</CHILD_ID> </ROW> <ROW> <ID>1</ID> <CHILD_ID>7</CHILD_ID> </ROW> <ROW> <ID>1</ID> <CHILD_ID>13</CHILD_ID> </ROW> </ROWSET>

或与普通 SQL 相同：

select
  id,
  dbms_xmlgen.getxml(dbms_xmlgen.newcontext(
    cursor(select * from t_child where t_child.id = t.id)
  )) as dependent_xml
from t

ID	DEPENDENT_XML
0	<?xml version="1.0"?> <ROWSET> <ROW> <ID>0</ID> <CHILD_ID>6</CHILD_ID> </ROW> <ROW> <ID>0</ID> <CHILD_ID>12</CHILD_ID> </ROW> </ROWSET>
1	<?xml version="1.0"?> <ROWSET> <ROW> <ID>1</ID> <CHILD_ID>1</CHILD_ID> </ROW> <ROW> <ID>1</ID> <CHILD_ID>7</CHILD_ID> </ROW> <ROW> <ID>1</ID> <CHILD_ID>13</CHILD_ID> </ROW> </ROWSET>

db小提琴here