Comments (2)
  • Add a Comment
  • Edit
  • More Actions v
  • Quarantine this Entry

1 Kalkals commented Permalink

Hi Serge,

 
This is a useful article. Thanks. We want to use the CONNECT_BY capability, and wanted to understand why it was not enabled by default in DB2 (sounds useful).
 
Regards,
Kals

2 SergeRielau commented Permalink

Kals,

 
The original reason, if I recall correctly, to limit the feature was that Oracle has some rather bizarre semantics for the content of the WHERE clause.
Namely if there is a local (non join) predicate it will be evaluated AFTER the recursion.
Any join predicates on the other hand will be processed before the recursion.
We found this sufficiently strange to not just make it default.
I think we're a bit more relaxed by now and perhaps at some point in the future we may remove the protective bit.
 
There are other blocks I want to remove such as ROWNUM, DUAL, and LIMIT/OFFSET
Cheers
Serge