Build graph has a specific separate path for `if self.connection is None:`, so that shouldn't be an issue? As far as atomicity, what if, in a case where no connection is found, it could just prompt: "No database connection found. Do you want your migration to be atomic? (y/N)" On Thursday, 9 December 2021 at 05:01:31 UTC-8 Jason wrote:
> It uses db connection in two places: > > building the migration graph > <https://github.com/django/django/blob/eba9a9b7f72995206af867600d6685b5405f172a/django/db/migrations/loader.py#L210-L215> > in > order to load previous applied migrations and transaction begin/end > wrapping > <https://github.com/django/django/blob/main/django/core/management/commands/sqlmigrate.py#L58-L60> > > This makes sense, because you can have N unapplied migrations between the > db and your migrations history package. > > > > On Tuesday, December 7, 2021 at 7:46:42 PM UTC-5 [email protected] > wrote: > >> Wondering why sqlmigrate needs a connection to an existing database. >> >> I understand that for certain commands, it needs the database to generate >> the migration. But for most (basic) commands, no connection is really >> needed. >> >> For example, I created a test project >> <https://github.com/ShmuelTreiger/test-django-project/tree/master/testproject/migrations>and >> >> generated migration files. Without ever running the `migrate` command, I >> was able to use `sqlmigrate` perfectly well on all migrations, save the >> last, which drops a `unique_together`. >> >> I'm sure there are other commands which actually need a database >> connection (though I haven't found them yet). Seems to me sqlmigrate could >> be rewritten along the lines of: >> >> - Try to generate sql from migration file >> - If it hits a command it needs the database, attempt to connect >> >> Or else: >> >> - If no connection, check if migration file needs connection to >> database >> >> Is there something I'm unaware of? >> >> >> This email may contain confidential material; unintended recipients must >> not disseminate, use, or act upon any information in it. If you received >> this email in error, please contact the sender and permanently delete the >> email. > > -- This email may contain confidential material; unintended recipients must not disseminate, use, or act upon any information in it. If you received this email in error, please contact the sender and permanently delete the email. -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/f338a5d3-5dd4-4270-a769-30f5584d651cn%40googlegroups.com.
