Re: Web2py ORM: Inheritance

[Massimo Di Pierro]

This concept does not exist in web2py but you may try

db.define_table('person',....)

fields=[db.person[key] for key in db.person.fields if key!='id']
fields.append(SQLField('company',....))

db.define_table('employee',*fields)

Let us know if it works.

On Jan 17, 2008, at 11:36 AM, Sharriff wrote:

> Yes I know that, I have used that extensively and it works, but thats
> not what I meant by subclassing(inheritance)
>
> Storm, SQLalchemy e.t.c all support this, a Storm example:
>
> 1 >>> class Person(object):
> 2 ... __storm_table__ = "person"
> 3 ... id = Int(primary=True)
> 4 ... name = Unicode()
>
>
> 1 >>> class Employee(Person):
> 2 ... __storm_table__ = "employee"
> 3 ... company_id = Int()
> 4 ... company = Reference(company_id, Company.id)
> 5 ...
> 6 ... def __init__(self, name):
> 7 ... self.name = name
>
>
>
> Employee is a subclass of "Person"
>
>
> I intend to subclass "Person" to "Parent" and "Child"
>
> Was that clear?
>
> On Jan 17, 2008 4:12 PM, Massimo Di Pierro
> <mdip...@cs.depaul.edu> wrote:
>> Not sure I understand
>>
>> db=SQLDB('....')
>>
>> parent=db.define_table('parent',SQLField
>> ('name2','string',length=20),SQLField('type2','string',lenght=20))
>>
>> then you use db.parent
>>
>> there is no need to import anything. Only SQLDB and SQLField are
>> visible in the scope.
>>
>>
>>
>> On Jan 17, 2008, at 3:48 AM, Sharriff wrote:
>>
>>> Hi Massimo, a quick question:
>>>
>>> Parent = SQLTable('parent',
>>> SQLField('name2', 'string', length = 20),
>>> SQLField('type2', 'string', length = 20)
>>> )
>>>
>>>
>>> What would be the proper "web2py" way to import SQLTable for use? I
>>> dont want to start doing things like "import gluon.sql.SQLTable",
>>> things would then be like Pylons.
>>>
>>>
>>> Thanks
>>
>>

[voltron]

Hmm, the problem I see with this method is that changes to the
"Person" class do not propagate to the "Employee" class as in other
ORMs, which is actually one of the points of using inheritance in a
case like this.