I think that this discussion has gotten seriously off-track. It is the
intent of the standard that the offset and window length values be
parameterized. This is clear from the standard language and I confirmed
this with the SQL committee in May. For the record, Lance and I sit on
the SQL committee as alternate delegates from Sun. Dynamic ? parameters
are Derby's model for specifying parameters.
I believe this is a serious usability defect of our OFFSET/FETCH
implementation. As it stands today, you can only scroll one of these
windows forward by sacrificing the performance benefits of prepared
statements. It would be a shame if this feature had to remain unusable
until the next rev of the standard in 2011. If the committee approves
some other language at that time, then we can implement that extension.
If people wish to veto this proposal, then I would ask them to propose
an alternative solution which makes this feature usable and which they
believe fits more comfortably within the intention of the standard.
Thanks,
-Rick
Dag H. Wanvik wrote:
Hi folks,
I have a working patch sitting on DERBY-4208. I am wondering if this
is a fix we should consider including for 10.5.2?
The pro argument is that this is a usability issue, and to the extent
it forces the app to construct SQL on the fly, makes the app more
vulnerable to injection attacks, at least in theory. A user has asked
for it.
On the contra side, we have the fact that dynamic arguments are not
allowed by the SQL standard for this construct, at least not yet.
Personally I think it's a nice extension.
Thoughts?
Dag
