Sorry, my original description may be a bit misleading. In summary, all I want is to create multiple table through Django's "Model" way.
Yes, I know this can be done using metaclass. I just did not know how to integrate it into Django's model, and the impacts. Fortunately, it seems Django has already covered this. Here is an entry on their wiki: http://code.djangoproject.com/wiki/DynamicModels Anyway, thank you all for the help. Huang On Thu, Dec 10, 2009 at 5:16 AM, bruno desthuilliers <bruno.desthuilli...@gmail.com> wrote: > On 9 déc, 20:18, HUANG Dong <huangdong...@gmail.com> wrote: >> Thank you, Bruno. Your answer is really helpful and covered another >> issue I hadn't noticed yet. But my question may be related to >> different topic. In my example, number of "libraries" is unknown in >> develop time, neither does the classification of "books". > > You explicitely mentionned that the reason to "partition" the books in > different tables was to speed up queries - and FWIW, I can't think of > any other reason to do so. If all you want is classification then > using different tables is not the correct solution. > >> To be more specific, I want to employ some kind of "introspective" >> class in python to model my data, and these dynamic classes should be >> associated to individual TABLEs in the database respectively. > > Yes, that's clearly what I understood. But this looks like a wrong > solution to a (potentially) real problem, hence my mention of RDBMS- > level table partitionning. > > >> So far what I know about Django is that each class inheriting from >> models.Model will be associated to a TABLE, and each instance of the >> class becomes an item when calling instance.save(). What if I create >> an introspective object in run-time? And when to call synchronization >> function to write the table into database? How to sync if there's >> concurrent creation of classes? What about the performance? All >> above are still unknown to me... > > Creating model classes at runtime is of course possible - if a bit > involved - since Python's "class" statement is an executable > statement. I'll even give you a couple hint: read the doc for the > 'type' type, and google for "metaclass". > > But I do insist on the fact that whether your _real_ problem is sql > queries performances tuning or classification, what you're trying to > achieve is _not_ the appropriate solution. > > -- > > You received this message because you are subscribed to the Google Groups > "Django users" group. > To post to this group, send email to django-us...@googlegroups.com. > To unsubscribe from this group, send email to > django-users+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/django-users?hl=en. > > > -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
