[sqlalchemy] Re: Declarative and common fields
i dont know if elixir has such 'attribute/behaviour injectors', i have DBCOOK_no_mapping=True in dbcook.sf.net that does that. the machinery behdin it is soewhat tricky (x in class.__dict__ and not in base_class.__dict__ etc stuff) u may try your stuff as mixin, that may or may not work. On Monday 29 September 2008 18:01:00 Joril wrote: Hi everyone! I'm new to SQLAlchemy and I'm using version 0.5rc1.. I need every entity class to have a few common fields, so I tried writing an abstract base class, declarative-style, that every other entity class would subclass. So for example: --- from sqlalchemy.ext.declarative import declarative_base from sqlalchemy import Column, String, DateTime, Integer ORMBase = declarative_base() class BaseObject(ORMBase): id = Column(Integer, primary_key=True) creation_time = Column(DateTime) modify_time = Column(DateTime) class TestEntity(BaseObject): value = Column(String) --- But SQLAlchemy complains that sqlalchemy.exc.ArgumentError: Mapper 'Mapper|BaseObject|None' does not have a mapped_table specified. (Are you using the return value of table.create()? It no longer has a return value.) Is there a way to tell SQLAlchemy to treat BaseObject like a non- mapped-class? I tried using ORMBase as mixin to TestEntity (so BaseObject extends object and TestEntity extends BaseObject and ORMBase), but now I get a sqlalchemy.exc.ArgumentError: Mapper Mapper|TestEntity|tests could not assemble any primary key columns for mapped table 'tests' so I guess that maybe I'm going down the wrong road.. Am I doing something that Declarative doesn't like? :) Should I try Elixir instead? Many thanks for your time! --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Declarative and common fields
On Mon, Sep 29, 2008 at 5:01 PM, Joril [EMAIL PROTECTED] wrote: Hi everyone! I'm new to SQLAlchemy and I'm using version 0.5rc1.. I need every entity class to have a few common fields, so I tried writing an abstract base class, declarative-style, that every other entity class would subclass. So for example: --- from sqlalchemy.ext.declarative import declarative_base from sqlalchemy import Column, String, DateTime, Integer ORMBase = declarative_base() class BaseObject(ORMBase): id = Column(Integer, primary_key=True) creation_time = Column(DateTime) modify_time = Column(DateTime) class TestEntity(BaseObject): value = Column(String) --- But SQLAlchemy complains that sqlalchemy.exc.ArgumentError: Mapper 'Mapper|BaseObject|None' does not have a mapped_table specified. (Are you using the return value of table.create()? It no longer has a return value.) Is there a way to tell SQLAlchemy to treat BaseObject like a non- mapped-class? I tried using ORMBase as mixin to TestEntity (so BaseObject extends object and TestEntity extends BaseObject and ORMBase), but now I get a sqlalchemy.exc.ArgumentError: Mapper Mapper|TestEntity|tests could not assemble any primary key columns for mapped table 'tests' so I guess that maybe I'm going down the wrong road.. Am I doing something that Declarative doesn't like? :) Should I try Elixir instead? I don't know whether this is currently possible with Declarative or not. In the case it isn't, patching Declarative should be quite easy (but I don't know if such a patch would be accepted or not). If you don't want to go down that route, Elixir does support that pattern. -- Gaëtan de Menten http://openhex.org --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Declarative and common fields
I don't know whether this is currently possible with Declarative or not. In the case it isn't, patching Declarative should be quite easy (but I don't know if such a patch would be accepted or not). I see.. I'll wait a bit then, maybe one of the developers will tell us if it'd be acceptable :) If you don't want to go down that route, Elixir does support that pattern. Do you mean these http://elixir.ematia.de/trac/wiki/FAQ#HowdoIaddfunctionalitytoallmyentitiestothebaseclass http://elixir.ematia.de/trac/wiki/FAQ#HowdoIprovideadifferentbaseclassthanEntity ? The comment Note that in this case you'll lose all default methods provided by the Entity class makes me think that extending Entity isn't supported even in Elixir, have I got it wrong? Thanks again! --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Declarative and common fields
On Sep 29, 2008, at 11:01 AM, Joril wrote: Hi everyone! I'm new to SQLAlchemy and I'm using version 0.5rc1.. I need every entity class to have a few common fields, so I tried writing an abstract base class, declarative-style, that every other entity class would subclass. So for example: --- from sqlalchemy.ext.declarative import declarative_base from sqlalchemy import Column, String, DateTime, Integer ORMBase = declarative_base() class BaseObject(ORMBase): id = Column(Integer, primary_key=True) creation_time = Column(DateTime) modify_time = Column(DateTime) class TestEntity(BaseObject): value = Column(String) --- But SQLAlchemy complains that sqlalchemy.exc.ArgumentError: Mapper 'Mapper|BaseObject|None' does not have a mapped_table specified. (Are you using the return value of table.create()? It no longer has a return value.) Is there a way to tell SQLAlchemy to treat BaseObject like a non- mapped-class? I tried using ORMBase as mixin to TestEntity (so BaseObject extends object and TestEntity extends BaseObject and ORMBase), but now I get a sqlalchemy.exc.ArgumentError: Mapper Mapper|TestEntity|tests could not assemble any primary key columns for mapped table 'tests' so I guess that maybe I'm going down the wrong road.. Am I doing something that Declarative doesn't like? :) Should I try Elixir instead? Many thanks for your time! the Column objects that are present on each declarative class are unique to that class, so the creation of those three Column objects would have to occur for each class. This suggests that the correct approach would be to extend the declarative metaclass to provide this behavior: from sqlalchemy import * from sqlalchemy.ext.declarative import DeclarativeMeta, declarative_base class MyDefaults(DeclarativeMeta): def __init__(cls, classname, bases, dict_): dict_['id'] = Column(Integer, primary_key=True) dict_['creation_time'] = Column(DateTime) dict_['modify_time'] = Column(DateTime) return DeclarativeMeta.__init__(cls, classname, bases, dict_) Base = declarative_base(metaclass=MyDefaults) class TestEntity(Base): __tablename__ = 'test' value = Column(String) print TestEntity.id == 5 print TestEntity.creation_time --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
