Thanks James and Russel for your replies. Am 04.10.2008 um 07:22 schrieb Russell Keith-Magee: > > On Sat, Oct 4, 2008 at 12:36 PM, Benjamin Buch <[EMAIL PROTECTED]> > wrote: >> >> Is there somewhere a place in the documentation where SQL migration >> strategies are explained a little? >> I think I remember a paragraph in the pre-1.0-documentation that >> described what you have to do with your database when you'd like to >> add a column to your model, but I can't find it anymore. > > This isn't the sort of thing that Django can document easily (and I > certainly can't recall it ever being mentioned in the Django docs). > The problem is that is isn't as simple as 'the SQL statement you need > to run' - every database does it quite differently.
Yes, documenting the whole thing would not be easy, you're absolutely right. But some hints on strategy would be very helpful I guess. Not in the sense of written SQL statements for every database, and not for every problem which could propably emerge when the models evolve. But I think there are some common patterns - like adding a field to a model - that could be described in a way that would be sufficient as an entry point to learning SQL. When I remember it right, then the paragraph I mentioned (I think it was in the tutorial...) was something like - alter your model - use manage.py sql altered_app to output the SQL statements you would use to create the table - alter the table along the lines of those statements At least this was a hint what to do... Or possibly another hint could be something like - dump the database tables you want to alter - put in the changes manually - delete the (now old) tables in your db - import the altered dump (I don't know if this works, but I will try...) So I'm not looking for a full-feldged documentation, just for some hints on strategy or some examples as a starting point to dive in deeper. >> Working with django for some weeks now, I find it quite common to >> want >> to add or modify a column after the db is synced and some (valuable) >> data is put in. >> Since it will propably take some time that the three great migration >> apps will merge(?) somehow and find their way into trunk (at least >> that's the way I understood it when watching the video from django >> con...), >> I dicided to do migration by hand. > > Merging Django Evolution, South and dmigrations is certainly something > that the three of us have discussed. We hope to be able to make some > public announcements about this in the near future. I'm looking forward to this! I liked the talk on django con... > In the meantime, any of the three migration projects are usable as-is. > >> I don't know SQL, and I find it quite hard to search for >> documentation >> (although there is good documentation about SQL out there...), think >> about migration strategies and tinker with differences between >> sqlite3 >> and mysql. >> So is there anywhere a short explanation of SQL from a django point >> of >> view out there? > > Your best source of documentation will be the SQL manual for your > database of choice, and/or the tutorials around the web for the same. > There's almost nothing Django specific about migrations at the SQL > level, other than knowing what you need your database to look like at > the end of the process (which you can find out using ./manage sqlall). As James said, I should stop and learn some SQL. Thanks for the tip on manage.py, it is quite useful. At least it shows how SQL statements should look... -benjamin --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
