formula?
On May 25, 1:16 pm, BearXu <bearx...@gmail.com> wrote:
> 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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