On Thursday, June 7, 2012 4:16:12 PM UTC-4, Alex Ogier wrote: > > This isn't particularly robust. The SQL string generated by a > particular backend isn't considered part of any API, and might change > formatting or semantics on minor updates. Some SQL is quite > complicated and dubiously related to the particular field, such as > extra INDEX or UNIQUE constraint statements. Certain backends elide > some arguments, performing constraint checking in the application (the > sqlite backend for example just drops many constraints). In general, > you want the migrations to be DB-agnostic, and checking SQL output > loses this feature. > > While the entire raw SQL generated by a field may be too unstable to inspect, the underlying SQL shouldn't be completely ignored. At the very least, the datatype needs to be inspected when freezing to detect if the rug has been pulled out from under the ORM.
A real world use case. Django-mssql uses the datetime datatype for datetime fields. Several years ago, Microsoft made the recommendation that all new work should use datetime2. A future version of django-mssql will switch to using datetime2. It would be great if the proposed migration framework handled that sort of switch, or at the very least displayed a warning about the need for manual user intervention. The same type of problem could be encountered if a database backend becomes unsupported and users are forced to switch to another backend where the maintainer follows a different set of "best practices". There are many ways of storing the same data that are all completely valid. The most likely problem field will be IPAddressField due to varchar(15) vs. unsigned int. Regards, Michael Manfre -- You received this message because you are subscribed to the Google Groups "Django developers" group. To view this discussion on the web visit https://groups.google.com/d/msg/django-developers/-/OzJ6JJwJxsYJ. To post to this group, send email to django-developers@googlegroups.com. To unsubscribe from this group, send email to django-developers+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-developers?hl=en.
