On Aug 1, 3:41 am, Ethan Furman <et...@stoneleaf.us> wrote: > Mornin'! and a good one, too, I hope. > > Question for you... > > First part of the question: What is the general value in having Null > capability for fields?
In general, in any database system, so that one can distinguish between "the customer has no 'middle name'" ('') and "the customer's 'middle name' is unknown" (NULL). > > Second part: Is there a tangible difference between Null, and the > nothing of 0, '', False, etc, in python? 0 is the zero thing, it is not nothing. False is not nothing. > > Third part: If there is a tangible difference, do those of us who use > python and these old, refuse-to-die, .dbf files actually have need of, > or have tables including, Null values? > > P.S. part (for John Machin, if he sees this ;) > Will the dbf package you are working on support Null values? My philosophy when digging stuff out of arcane storages is to expose what is found and leave any kludging/sanitising to the next layer. For example, None is returned for an N (Number) field that's all spaces; it's up to the caller to decide whether to treat None as zero, raise an exception, pop up a data-collection dialogue box, ... If you mean specifically the Visual Foxpro v3 _NullFlags hack, yes, it already supports that, as well as the VFP9 abuse of that hack for Varchar and Varbinary fields :-) -- http://mail.python.org/mailman/listinfo/python-list