On Feb 19, 2011, at 18:57 , Michael Bayer wrote:
>
> On Feb 19, 2011, at 12:45 PM, Martijn Moeling wrote:
>
>> Hi,
>>
>> I am running into something weird results I do not really understand. SA
>> 0.6.6
>>
>>
>> I have a Polymorhic table setup, where I need to get the columnlist for
>> outputting the ExtJs 4 Model.
>>
>> Basically it should output
>>
>>
>> ( 'User' : { fields : [
>> {'field1' : 'int'},
>> {'field2' : 'string'},
>> {'field3' : 'boolean'}
>> ]
>> }
>> )
>>
>>
>> to output the data to the browser in json I do
>>
>> dict(Userinstance)
>>
>>
>> to get this working I have added to the BaseClass of the polymorphic setup
>>
>> def __iter__(self):
>> for c in self.__table__.columns + BaseClass.__table__.columns:
>> if c.name not in ['discriminator']:
>> if isinstance(c.type, DateTime):
>> value = getattr(self, c.name).strftime("%Y-%m-%d
>> %H:%M:%S")
>> else:
>> value = getattr(self, c.name)
>> yield(c.name, value)
>>
>> This works fine but a few things has to be taken in consideration:
>>
>> Both self.__table__.columns and BaseClass.__table__.columns__ have columns
>> defined in the BaseClass
>> In the above, this is no real problem since the dict keys are overwritten
>> and they have the same value anyway.
>>
>> if I do the same for generating a model:
>>
>> def ExtModel(self):
>> Result = {'fields': []}
>> for c in self.__table__.columns + BaseClass.__table__.columns:
>> if c.name not in ['discriminator']:
>> if isinstance(c.type, Unicode):
>> Result['fields'].append({'name': c.name, 'type':
>> 'string'})
>> elif isinstance(c.type, Integer):
>> Result['fields'].append({'name': c.name, 'type': 'int'})
>> elif isinstance(c.type, Boolean):
>> Result['fields'].append({'name': c.name, 'type':
>> 'boolean'})
>> elif isinstance(c.type, Float):
>> Result['fields'].append({'name': c.name, 'type':
>> 'float'})
>> elif isinstance(c.type, DateTime):
>> Result['fields'].append({'name': c.name, 'type': 'date'})
>> return self.__class__.__name__, Result
>>
>> I get the Id field twice..... in the fieldlist
>> again they have the same value, but here it alters the result.
>>
>>
>> I need something like:
>> def ExtModel(self):
>> ColumnList = self.__table__.columns
>> for c in BaseClass.__table__.columns:
>> if c not in self.__table__.columns:
>> ColumnList.append(c)
>> Result = {'fields': []}
>> for c in self.__table__.columns + Affiliation.__table__.columns:
>> ...... etc
>>
>>
>> which gives:
>> if c not in self.__table__.columns:
>> File
>> "/Library/Python/2.6/site-packages/SQLAlchemy-0.6.6-py2.6.egg/sqlalchemy/sql/expression.py",
>> line 2064, in __contains__
>> raise exc.ArgumentError("__contains__ requires a string argument")
>> sqlalchemy.exc.ArgumentError: __contains__ requires a string argument
>
> columns.contains_column(c)
interesting method....
>
>>
>>
>> One other thing i noted which is really odd....
>>
>> I have multiple classes inheriting from BaseClass, which is why I have set
>> up polymorphic inheritance in the foist place.
>>
>> When I do:
>>
>> alldata = s.query(BaseClass).all()
>> for a in alldata:
>> print a.ExtModel()
>>
>>
>> I notice that BaseClass.__table__.columns sometimes holds the Id in others
>> it doesnt.
>
> i don't understand what "sometimes" means. BaseClass.__table__.columns is a
> collection created only once.
me neither, That Is why I brought it up
>
>
>>
>> most of the classes (new project) are "empty" anyway and are no more than:
>>
>> SomeClass(BaseClass):
>> Id = Column(Integer, ForeignKey('baseclass.Id'), primary_key=True)
>>
>> SomeClass2(BaseClass):
>> Id = Column(Integer, ForeignKey('baseclass.Id'), primary_key=True)
>>
>> That is really weird!!!!! It solves my problem automatically on some
>> instances but not on others and only for the Id column .......
>
>
>
>
>>
>>
>>
>> Is there a way I can make a new ColumnList based on the
>> self.__table__.columns and BaseClass.__tablename__ excluding the overlap. In
>> this example I 'only' talk about the Id but in my real world there are more
>> Columns in BaseClass
>
> i dunno, [c for c in self.__table__.columns] + [c for c in
> BaseClass.__table__.columns if c.key not in self.__table__.columns] ?
yep! this works:
def ExtModel(self):
ColumnList = [c for c in self.__table__.columns] + [c for c in
BaseClass.__table__.columns if c.key not in self.__table__.columns]
Result = {'fields': []}
for c in ColumnList:
if c.name not in ['discriminator']:
if isinstance(c.type, Unicode):
Result['fields'].append({'name': c.name, 'type': 'string'})
elif isinstance(c.type, Integer):
Result['fields'].append({'name': c.name, 'type': 'int'})
elif isinstance(c.type, Boolean):
Result['fields'].append({'name': c.name, 'type': 'boolean'})
elif isinstance(c.type, Float):
Result['fields'].append({'name': c.name, 'type': 'float'})
elif isinstance(c.type, DateTime) or isinstance(c.type, Date)
or isinstance(c.type, Time) :
Result['fields'].append({'name': c.name, 'type': 'date'})
return self.__class__.__name__, Result
Does the trick!
>
>
>
>>
>>
>> Martijn
>>
>>
>>
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