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From: Jon R. F. <drj...@gm...> - 2007-07-07 18:34:12
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I have two simple SQLObject classes, WebTag and WebTopic that are
related using a RelatedJoin:
class WebTag(SQLObject):
Name = StringCol( alternateID=True)
Topics = RelatedJoin('WebTopic')
class WebTopic(SQLObject):
Name = StringCol( unique=True )
Format = StringCol( default="rst" )
Title = StringCol( )
Subtitle = StringCol( default=None)
Description = StringCol(default=None)
Keywords = StringCol( default=None )
Author = StringCol( default=None )
DateTimePosted = DateTimeCol()
DateTimeLastModified = DateTimeCol()
UUID = StringCol()
Content = StringCol( default=None )
Tags = RelatedJoin('WebTag')
What is the appropriate way to delete an instance of a WebTopic or a
WebTag so that RelatedJoin won't be broken?
Right now I have a simple:
WebTopic.delete(id_to_delete)
or a
WebTag.delete(id_to_delete)
But I just started getting this error, so I must have missed something
in the documentation:
>>> for a in WebTag.selectBy(Name='python'):
... print a.Name
... print a.Topics
...
python
Traceback (most recent call last):
File "<stdin>", line 3, in <module>
File "<string>", line 1, in <lambda>
File "/usr/lib/python2.5/site-packages/sqlobject/joins.py", line
207, in performJoin
return self._applyOrderBy([self.otherClass.get(id, conn) for (id,)
in ids if id is not None], self.otherClass)
File "/usr/lib/python2.5/site-packages/sqlobject/main.py", line 913, in get
val._init(id, connection, selectResults)
File "/usr/lib/python2.5/site-packages/sqlobject/main.py", line 958, in _init
raise SQLObjectNotFound, "The object %s by the ID %s does not
exist" % (self.__class__.__name__, self.id)
sqlobject.main.SQLObjectNotFound: The object WebTopic by the ID 12
does not exist
>>>
Any help and suggestions would be appreciated. The db can be wiped and
started over, because this is a little test system. Should I have
dropped all references to the missing WebTopic instance from all
WebTag instances?
- Jon
--
Jon R. Fox
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Re: [SQLObject] The proper way to delete an instance of an
SQLObject that is linked as a RelatedJoin
From: Daniel N. <no...@gm...> - 2007-07-09 10:09:28
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> I have two simple SQLObject classes, WebTag and WebTopic that are
> related using a RelatedJoin:
>
>
> class WebTag(SQLObject):
> Name = StringCol( alternateID=True)
> Topics = RelatedJoin('WebTopic')
>
> class WebTopic(SQLObject):
> Name = StringCol( unique=True )
> Format = StringCol( default="rst" )
> Title = StringCol( )
> Subtitle = StringCol( default=None)
> Description = StringCol(default=None)
> Keywords = StringCol( default=None )
> Author = StringCol( default=None )
> DateTimePosted = DateTimeCol()
> DateTimeLastModified = DateTimeCol()
> UUID = StringCol()
> Content = StringCol( default=None )
> Tags = RelatedJoin('WebTag')
>
> What is the appropriate way to delete an instance of a WebTopic or a
> WebTag so that RelatedJoin won't be broken?
>
> Right now I have a simple:
>
> WebTopic.delete(id_to_delete)
>
> or a
>
> WebTag.delete(id_to_delete)
>
> But I just started getting this error, so I must have missed something
> in the documentation:
>
> >>> for a in WebTag.selectBy(Name='python'):
> ... print a.Name
> ... print a.Topics
> ...
> python
> Traceback (most recent call last):
> File "<stdin>", line 3, in <module>
> File "<string>", line 1, in <lambda>
> File "/usr/lib/python2.5/site-packages/sqlobject/joins.py", line
> 207, in performJoin
> return self._applyOrderBy([self.otherClass.get(id, conn) for (id,)
> in ids if id is not None], self.otherClass)
> File "/usr/lib/python2.5/site-packages/sqlobject/main.py", line 913, in
> get
> val._init(id, connection, selectResults)
> File "/usr/lib/python2.5/site-packages/sqlobject/main.py", line 958, in
> _init
> raise SQLObjectNotFound, "The object %s by the ID %s does not
> exist" % (self.__class__.__name__, self.id)
> sqlobject.main.SQLObjectNotFound: The object WebTopic by the ID 12
> does not exist
> >>>
>
> Any help and suggestions would be appreciated. The db can be wiped and
> started over, because this is a little test system. Should I have
> dropped all references to the missing WebTopic instance from all
> WebTag instances?
Yes, you need to delete everything manually that is referenced by
anything that is to be deleted.
A question to the experts: I usually do this by overloading
destroySelf so that it loops over all references, is that a good idea?
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Re: [SQLObject] The proper way to delete an instance of an
SQLObject that is linked as a RelatedJoin
From: Oleg B. <ph...@ph...> - 2007-07-09 10:46:14
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On Sat, Jul 07, 2007 at 02:34:11PM -0400, Jon R. Fox wrote:
> What is the appropriate way to delete an instance of a WebTopic or a
> WebTag so that RelatedJoin won't be broken?
.destroySelf() in SQLObject 0.7.2 was extended to automatical remove
rows from the intermediate table. Does it work?
Oleg.
--
Oleg Broytmann http://phd.pp.ru/ ph...@ph...
Programmers don't die, they just GOSUB without RETURN.
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Re: [SQLObject] The proper way to delete an instance of an
SQLObject that is linked as a RelatedJoin
From: Oleg B. <ph...@ph...> - 2007-07-09 10:47:09
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On Mon, Jul 09, 2007 at 12:09:25PM +0200, Daniel Nogradi wrote:
> Yes, you need to delete everything manually that is referenced by
> anything that is to be deleted.
No, you don't. .destroySelf() in SQLObject 0.7.2 was extended to
automatically remove rows from the intermediate table. Does it work?
Oleg.
--
Oleg Broytmann http://phd.pp.ru/ ph...@ph...
Programmers don't die, they just GOSUB without RETURN.
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Re: [SQLObject] The proper way to delete an instance of an
SQLObject that is linked as a RelatedJoin
From: Jon R. F. <drj...@gm...> - 2007-07-09 12:28:53
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On 7/9/07, Oleg Broytmann <ph...@ph...> wrote: > On Mon, Jul 09, 2007 at 12:09:25PM +0200, Daniel Nogradi wrote: > > Yes, you need to delete everything manually that is referenced by > > anything that is to be deleted. > > No, you don't. .destroySelf() in SQLObject 0.7.2 was extended to > automatically remove rows from the intermediate table. Does it work? I switched to WebTag.get(tag_id_to_delete).destroySelf() and that works great in SQLObject-0.10dev_r2730 that the python easy_install upgrade leads to. Unfortunately Ubuntu Feisty Fawn is still stuck on 0.7.1 on their distro. Best Regards, Jon |
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Re: [SQLObject] The proper way to delete an instance of an
SQLObject that is linked as a RelatedJoin
From: Oleg B. <ph...@ph...> - 2007-07-09 12:31:18
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On Mon, Jul 09, 2007 at 08:28:51AM -0400, Jon R. Fox wrote:
> I switched to
>
> WebTag.get(tag_id_to_delete).destroySelf()
This is equivalent to
WebTag.delete(tag_id_to_delete)
Oleg.
--
Oleg Broytmann http://phd.pp.ru/ ph...@ph...
Programmers don't die, they just GOSUB without RETURN.
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Re: [SQLObject] The proper way to delete an instance of an
SQLObject that is linked as a RelatedJoin
From: Jon R. F. <drj...@gm...> - 2007-07-09 12:42:58
|
Excellent. I tried changing syntax first, which didn't work, and then realized that the version of sqlobject installed on this machine was stale. I'm glad they are equivalent, because I enjoy terseness. Filing an upgrade bugrequest for the ubuntu people is now on my todo list. With the popularity of turbogears, a lot of folks are going to try a related join and then reach this problem. -- Jon On 7/9/07, Oleg Broytmann <ph...@ph...> wrote: > On Mon, Jul 09, 2007 at 08:28:51AM -0400, Jon R. Fox wrote: > > I switched to > > > > WebTag.get(tag_id_to_delete).destroySelf() > > This is equivalent to > > WebTag.delete(tag_id_to_delete) > > Oleg. > -- > Oleg Broytmann http://phd.pp.ru/ ph...@ph... > Programmers don't die, they just GOSUB without RETURN. > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > sqlobject-discuss mailing list > sql...@li... > https://lists.sourceforge.net/lists/listinfo/sqlobject-discuss > -- Dr. Jon R. Fox Applied Physicist and Technologist drj...@gm... http://www.drfox.com 1-973-494-0370 |
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Re: [SQLObject] The proper way to delete an instance of an
SQLObject that is linked as a RelatedJoin
From: Daniel N. <no...@gm...> - 2007-07-10 09:06:19
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> > Yes, you need to delete everything manually that is referenced by
> > anything that is to be deleted.
>
> No, you don't. .destroySelf() in SQLObject 0.7.2 was extended to
> automatically remove rows from the intermediate table. Does it work?
Maybe I'm misunderstanding you but if a foreignkey points to an object
that is deleted, the object that refers to the deleted object will not
be:
from sqlobject import *
sqlhub.processConnection = connectionForURI( 'sqlite:/:memory:' )
class city( SQLObject ):
buildings = MultipleJoin( 'building' )
class building( SQLObject ):
city = ForeignKey( 'city' )
city.createTable( )
building.createTable( )
c = city( )
b1 = building( city=c )
b2 = building( city=c )
c.destroySelf( )
print building.select( ).count( )
print b1.city
This will print 2 and then an SQLObjectNotFound exception will be
raised so you need to manually delete all buildings that refer to a
deleted city. I guess you had RelatedJoin in mind.
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Re: [SQLObject] The proper way to delete an instance of an
SQLObject that is linked as a RelatedJoin
From: Oleg B. <ph...@ph...> - 2007-07-10 09:15:15
|
On Tue, Jul 10, 2007 at 11:06:17AM +0200, Daniel Nogradi wrote:
> Maybe I'm misunderstanding you but if a foreignkey points to an object
> that is deleted, the object that refers to the deleted object will not
> be:
This has nothing with RelatedJoin. You case is much simpler to fix:
> class building( SQLObject ):
> city = ForeignKey( 'city' )
city = ForeignKey( 'city' , cascade=True)
Oleg.
--
Oleg Broytmann http://phd.pp.ru/ ph...@ph...
Programmers don't die, they just GOSUB without RETURN.
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Re: [SQLObject] The proper way to delete an instance of an
SQLObject that is linked as a RelatedJoin
From: Daniel N. <no...@gm...> - 2007-07-10 10:39:26
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> > Maybe I'm misunderstanding you but if a foreignkey points to an object > > that is deleted, the object that refers to the deleted object will not > > be: > > This has nothing with RelatedJoin. You case is much simpler to fix: > > > > class building( SQLObject ): > > city = ForeignKey( 'city' ) > > city = ForeignKey( 'city' , cascade=True) Thanks a lot, this is really great, I didn't know about the cascade option, I was always overriding destroySelf. And of course you are right, this is specific to MultipleJoin and the OP was talking about RelatedJoin. Thanks again. |
