On Fri, Sep 11, 2009 at 1:42 AM, mdipierro <[email protected]> wrote:
> > On Sep 11, 1:19 am, Richard <[email protected]> wrote: > > > on delete cascade in SQLite > > > > Fantastic! My feature request for this can be closed: > http://code.google.com/p/web2py/issues/detail?id=50 > > Can you do it or should I do it? > > > Did the solution involve sqlite triggers? > > No. The solution is quite dumb. recursively delete all referencing > records. I guess it could be improved using triggers. > Yes - I was going to mention this too when I saw it.... There is a pattern on SQLite pages somewhere (I pointed someone to them once). My immediate concern is about web2py only activity taking care of an external db - and what is another app is cooperating on the DB (like we are doing for PyCon - either web2py or django...)... What is the db exists, and already has triggers to handle cascade? What happens then? What is another application assumes / depends on the DB to have the tirggers (so one - web2py - does the cascade action, but the other doesn't). Make sense? I think this needs more thought. - Yarko > > > > > > row = db(db.mytable.id>0).select().first() > > > > very convenient > > > > Richard > > > > On Sep 11, 3:12 pm, mdipierro <[email protected]> wrote: > > > > > I have made some changes to the code in trunk: > > > > > 1) Since tonight I attended a presentation about how SQLAlchemy can do > > > on delete cascade in SQLite even if SQLite does not support it, I > > > implemented this feature in web2py too. There is nothing you have to > > > do it now there by default. For example: > > > > > db=DAL('sqlite://test.db') > > > db.define_table('a',Field('name')) > > > db.define_table('b',Field('a',db.a,ondelete='CASCADE'),Field('name')) > > > db.a.insert(name='xxx1') > > > db.a.insert(name='xxx2') > > > db.a.insert(name='xxx3') > > > db.a.insert(name='xxx4') > > > db.b.insert(a=2,name='yyy1') #(1) > > > db.b.insert(a=2,name='yyy2') #(1) > > > db.b.insert(a=3,name='yyy3') > > > db(db.a.id==2).delete() > > > for row in db(db.b.a==2).select(): print row # prints nothing as it > > > should > > > > > Notice ondelete='CASCADE' is default. > > > > > 2) you can now do: > > > > > row = db(db.mytable.id>0).select().first() > > > row = db(db.mytable.id>0).select().last() > > > > > and row is None if no records are selected. > > > > > 3) I fixed the problem with the memory leak reported by zahariash > > > > > 4) I refactored some code in main.py, compileapp.py and globals.py. > > > This should make the code cleaner. Hopefully I did not break it. > > > Please give it a try. > > > > > Massimo > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py-users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
