Can I save a formula in it?
2009/5/25 mdipierro <mdipie...@cs.depaul.edu>
>
> you are right. it was just an example
>
> On May 25, 12:45 am, Alexey Nezhdanov <snak...@gmail.com> 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 <mdipie...@cs.depaul.edu> 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
> >
> >
> >
>
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