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.
>
> > 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
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