can we design a custom column that can save a function in it? Thus the customer can create or modify their own function to manipulate other data in the database.
So such kind of field saves the code instead of the value. 2009/5/25 mdipierro <[email protected]> > > formula? > > On May 25, 1:16 pm, BearXu <[email protected]> wrote: > > Can I save a formula in it? > > > > 2009/5/25 mdipierro <[email protected]> > > > > > > > > > you are right. it was just an example > > > > > On May 25, 12:45 am, Alexey Nezhdanov <[email protected]> wrote: > > > > I think that's handy. Dropping cross-db compartibility is bad indeed, > > > > but you just need to have a big warning in the place where user have > > > > to make that choice. > > > > > > Also - I don't think that you can safely replace ' with " on pickled > > > > object. Most likely you are ruining it. Either proper sql escaping > > > > should be introduced or better yet - base64 encoding. If I am not > > > > mistaken - pickled objects are binary. > > > > > > On May 25, 9:17 am, mdipierro <[email protected]> wrote: > > > > > > > I do not know if this is a good idea and I'd like to hear your > > > > > opinions: > > > > > I have added in trunk to define custom column types > > > > > > > Here is an example of usage: > > > > > > > import cPickle > > > > > from gluon.sql import SQLCustomType > > > > > from decimal import Decimal > > > > > > > decimal = SQLCustomType(native='NUMERIC(10,2)',decoder=(lambda x: > > > > > Decimal(str(x)))) > > > > > > > pickable = SQLCustomType(type='text',encoder=(lambda x: > > > > > "'%s'"%cPickle.dumps(x).replace("'","''")),decoder=(lambda x: > > > > > cPickle.loads(x))) > > > > > > > db.define_table('test', > > > > > SQLField('my_decimal',type=decimal), > > > > > SQLField('my_pickle',type=pickable)) > > > > > > > the SQLCustomType constructor takes the following arguments: > > > > > - type indicates how web2py sqlform should treat this field > > > > > - native indicates how the database should treat this field > > > > > - encoder indicates how to represent (and escape) a value in SQL > > > > > - decoder indicates how to process the value once it is extracted > from > > > > > the database > > > > > > > It seems to work well with migrations. Of course using native=.... > > > > > makes the custom table not portable across databases. > > > > > > > The implementation is not very clean but can be improved. > > > > > > > Is this a good idea? > > > > > > > Massimo > > > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py Web Framework" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
