SQL * Loader加载缺少标记的XML

Question

我正在分析通过SQL * Loader加载XML数据的问题。

问题是文件内容是否可变：

<customer>
  <name>abc</name>
  <surname>abc</surname>
  <address>abc</address>
</customer>
<customer>
  <name>abc</name>
  <address>abc</address>
</customer>

如果找不到姓氏节点，则未加载记录，日志文件显示

Record 1: Rejected - ...Initial enclosure character not found

如果找不到标记，我想使用默认值。 “null if”不起作用。我怎么能这样做？

这是我的控制文件：

FIELDS (
  dummy1   filler  terminated by "<customer>",  
  name             enclosed by "<name>" and "</name>",  
  surname          enclosed by "<surname>" and "</surname>" NULLIF (surname = "unknown"),
  address          enclosed by "<address>" and "</address>", 
  dummy2   filler  terminated by "</customer>"
)