I remember a post about an ORM layer class on top of DAL, that allowed
for dynamic selects django style, I can't find the post though, can
anyone remember what it was called?
-Thadeus
On Tue, Feb 9, 2010 at 9:11 AM, tiago almeida <tiago.b.alme...@gmail.com> wrote:
> Hello all,
>
> I've been thinking about implementing a module that takes a DAL table
> definition and generates a class object from that definition. The purpose of
> this is to use those automatically generated classes in the controllers
> instead of accessing the DAL directly. Eg: Creating an instance of that
> class could make an insertion in the db transparently; setting attributes on
> that instance triggers db updates, etc..
> One important feature is that every table Row is mapped to an instance of
> some class and this layer is completely opaque, i.e. it can't expose any
> Rows/Row/Field objects to the client.
>
> A more concrete example of whats being pursued:
> -----------------
> db.define_table( "Person", Field('name') )
> db.define_table( "Dog", Field("name"), Field("Owner",db.Person) )
>
> createClass(db.Person)
> createClass(db.Dog)
>
> #and now you can do:
>
> p = Person("John") #selects person with name="John", possibly
> throwing exception or creating such a record (have to weigh the pros and
> cons)
> johns_dogs = p.dog_list #johns_dogs is a list of Dog instances
> johns_dogs[0].name #returns name of one of the john's dogs.
> johns_dogs[0].name = "new name" #updates this dogs name in db
> -----------------
>
> I've had some success a this, namely, made a function that takes a Rows
> object and returns a list of Storage instances where each storage has the
> same attributes as the corresponding Row fields and, whenever the value of a
> Row's Field is a Sql.Set, it .selects() it and continues recursively until
> everything is converted into a big tree of Storage instances.
>
> This is where I ask for some help. Ideally I don't want to convert every Row
> into a Storage, I'd like a Row of table Product (e.g.) to be converted into
> an instance of class Product (which was automatically generated when table
> Product was defined). Yet, I do not know of an easy way to get the Table
> from which a specific Row came from. Is it possible without major hacks in
> the DAL?
>
> Also, since you're at it, what do you think about this? My motivation is
> that it gets tiring to be defining helper functions to make the controller
> code simpler and then be constantly updating those helper functions whenever
> the model changes.
>
>
> Thanks a lot in advance,
> Tiago
>
>
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