[Zope] optional arguments to zsql methods

J Cameron Cooper zope-l at jcameroncooper.com
Wed Feb 22 20:10:35 EST 2006

garry wrote:
> I am importing a large data set via Zope into a Postgres database. Data
> items may or may not exist so I am using the optional argument in the
> zsql methods. What I want is that if the data is missing the database
> inserts default values.
> However,
> if type="string", the absent data item is rendered as ''
> if type="nb", the absent data item is rendered as 'Null'
> In either case this does not allow default values to be inserted. I can
> insert the defaults by doing this:
> .....ZSQL.....
> snip.....
> <dtml-if surnamefirst>
>  <dtml-sqlvar  surnamefirst   type="string"> ,
> <dtml-else>
> </dtml-if>
> With 20 or so inserts in one query this gets messy and could be slow? if
> this method has to be called many times on one import cycle.
> My question is therefore is there a cleaner way of doing this or am I on
> the right track?

The parameters themselves accept a default value; the trick, of course, 
is that they have to be not passed, rather than just false. Depending on 
your upstream code, this may or may not be trivial.

If you have a bunch of empty values being passed in, you can fix this 
with a Python script facade:

   for key, value in kw:
      if not value: del kw[key]

There may be more clever or efficient ways to write the python, but that 
should work.

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