When I have models like this:
class Foo(meta.Model)
...
class Bar(meta.Model):
foos = meta.ManyToManyField(Foo)
class Baz(meta.Model)
bar = meta.ForeignKey(Bar, edit_inline=True)
object creation will go something like this:
obj = Bar(...)
obj.save() # a must, or below code will complain about obj not having
a ID
obj.add_baz(some_function(),...)
foos = some_other_function()
obj.set_foos(foos)
OK so far, but:
obj = Bar(...)
obj.save()
obj.add_baz(some_function(),...)
foos = some_other_function() # AND THIS THROWS A EXCEPTION
obj.set_foos(foos)
Then I have obj, with some of baz objects added but no Foo's!!
Currently I have to write something like this:
obj = Bar(...)
obj.save()
try:
obj.add_baz(some_function(),...)
except:
obj.delete()
raise
try:
foos = some_other_function()
obj.set_foos(foos)
except:
# find and delete related baz objects
obj.delete()
Wow, it's just like Java ;)
IMHO we have two solutions here, use transactions (and probably
easier to implement) like this:
BEGIN TRANSACTION;
try:
obj = Bar(...)
obj.save() # a must!
obj.add_baz(some_function(),...)
foos = some_other_function()
obj.set_foos(foos)
COMMIT;
except:
ROLLBACK;
Or something like this which is to me more logical and pythonic:
try:
obj = Bar(...)
obj.add_baz(some_function(),...)
foos = some_other_function()
obj.set_foos(foos)
obj.save() # this will save obj and then save all baz and foo objects
except:
# try to recover from error, report, do something! :)
What I want here is that I don't need to call .save() (and store
object data in database) before adding M2M and related FK data.
Or there is a another solution for this?
---
Nebojša Đorđević - nesh
Studio Quattro - Niš - SCG
http://studioquattro.biz/
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Registered Linux User 282159 [http://counter.li.org]
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