[Zope-DB] Error on traversing to ZSQL?

[Qingliang Li]

<>I try a example (Traversing to Result Objects) in the the Chapter 
--"Relational Database Connectivity" of** The Zope Book (2.6 Edition) 
<http://zope.org/Documentation/Books/ZopeBook/2_6Edition>
**


I followed the example step by step, but when I use the traversing:
http://localhost:8080/employee_by_id/emp_id/42/viewEmployee

I meet the following errors,  how can  get it? Many Thanks!


    Site Error

An error was encountered while publishing this resource.

*Error Type: KeyError*
*Error Value: '_r'*

------------------------------------------------------------------------

Troubleshooting Suggestions

    * This resource may be trying to reference a nonexistent object or
      variable *'_r'*.
    * The URL may be incorrect.
    * The parameters passed to this resource may be incorrect.
    * A resource that this resource relies on may be encountering an error.

For more detailed information about the error, please refer to the error 
log.

If the error persists please contact the site maintainer. Thank you for 
your patience.




-- 
Qingliang Li
Center for Theoretical Biology,
Peking University, Beijing,
P.R.China, 100871

Email: qlli at ctb.pku.edu.cn
Tel: +86-010-6275-9669