I suggested it 2 years ago. I'll be happy if it come true someday, in web2py.
I see it as database triggers: before_<event> & after_<event>. I.e:
before_insert, after_insert. Event can be: insert, update, delete,
query.
"before_insert" receives values that will be inserted on database. It
is the last chance to modify, check some value or make run some
routine before register is inserted.
"after_insert" receives values just stored there.
"before_update" receives data stored on the database, before the
record is updated. As "before_insert", this is a last chance event.
"after_update" receives data contents after the update took place.
"before_delete" receives data stored on the database. As
"before_update" does. Also, it's a last chance event.
"after_delete" receives same data, but after register was deleted.
"before" and "after" query I don't see as important. Web2py already
has virtual and computed fields. But would be nice to log accesses to
some table.
I worked with these triggers on Sybase, many years ago. But I remember
how it was nice to make stored procedures and triggers counting on
these events (except query events. I just saw it on Oracle),
guaranteeing db integrity.
--
Vinicius Assef.
On Tue, Oct 11, 2011 at 7:42 PM, Massimo Di Pierro
<massimo.dipie...@gmail.com> wrote:
> the problem with this is not the names. ;-)
>
> Consider the case of preupdate and onupdate.
>
> db(db.person.age>18).update(can_drink=True)
>
> What information should be passed to preupdate and update? tablename?
> query? {'can_drink':True}? Number of affected records? Should there be
> one onselect per table? We do not want to call onupdate for every
> table, do we (performance issues)?
>
> What about?
>
> db(db.person.id=2).update(can_drink=True)
>
> What about
>
>
> db(db.person).select(left=db.dog.on(db.dog.owner==db.person.id),limitby=(0,1))
>
> What should we pass to onselect? query? left? limitby? all arguments?
> number of returned records? returned records? In this case we cannot
> pass one table because because more than one table may be involved.
>
> Every one of those callbacks would need a different signature. It
> would not be obvious and I am not sure people would agree.
> I do not oppose to this. I just want to hear more from you.
>
> Massimo
>
>
>
> On Oct 11, 4:57 pm, Bruno Rocha <rochacbr...@gmail.com> wrote:
>> Would be nice to have some global events in web2py workflow. I can imagine
>> some useful hooks:
>>
>> workflow global events:
>>
>> onrequest # before the execution of action/model
>>
>> prerender # after the execution of action/model but before the view
>> rendering
>>
>> onrender # after the view render but before the output
>>
>> onresponse # after all the request process finished.
>>
>> DAL global events:
>>
>> preselect - onselect
>> preinsert - oninsert
>> preupdate - onupdate
>> predelete - ondelete
>>
>> ASPnet has some usefull event system (oninit, onload, pageload etc..)
>>
>> I dont even know if it is possible to trigger all of them in web2py and how
>> can it cost. but would be nice to have it.
>>
>> http://zerp.ly/rochacbruno
>> Em 11/10/2011 17:23, "Massimo Di Pierro" <massimo.dipie...@gmail.com>
>> escreveu:
>>
>>
>>
>>
>>
>>
>>
>> > Not yet at the db level but at the form level:
>>
>> > form=SQLFORM(...).process(onsuccess=lambda form:...)
>>
>> > On Oct 11, 3:11 am, Manuele <manuele.pese...@gmail.com> wrote:
>> > > Hi,
>> > > is there a way to trigger some functions on database eventes, for
>> > > example on new record?
>>
>> > > thanks a lot
>>
>> > > Manuele
