On 07/04/2017 07:04 AM, Patryk Zawadzki wrote:
> Have DB backends understand certain field types expressed as strings
> ("varchar", "text", "blob", "decimal" and so on).
>
> Possibly some backends could implement a wider set than the others
> ("json", "xml", "rasterimage" etc.).
>
> Have each Field class deconstruct to a field name and params, eg:
> "decimal", {"digits": 12, "decimals": 2}.
>
> Then a model becomes essentially a list of tuples:
>
> [
> ("title", "varchar", {"length": 100}),
> ("price", "decimal", {"digits": 12, "decimals": 2}),
> ...
> ]
>
> This is not far from what "render model states" does currently except
> that it compares much richer model descriptions that leads to no-op
> migrations being generated each time you change a label or a
> user-visible part of choices.Right, and one reason for generating those "no-op" migrations is that they aren't actually no-ops, if you value being able to write data migrations in Python using the ORM. They keep the historical Python models accurate. Of course, we do pay a cost in complexity for the "historical ORM" feature, and it's reasonable to prefer a tradeoff that doesn't pay that cost and requires all data migrations to be written in SQL. As Andrew mentioned, there's nothing to prevent anyone from writing an alternative migrations frontend that takes this approach. It should be able to reuse the schema editor backend, which does the heavy lifting of cross-db schema alteration. It's worth remembering, though, that five or six years ago we _had_ a range of different migrations solutions that chose different tradeoffs, and South was the clear winner in user uptake. It's not due to arbitrary whim that the Django migrations system is based on South and preserves its popular features, like the historical ORM. Carl -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To post to this group, send email to django-developers@googlegroups.com. Visit this group at https://groups.google.com/group/django-developers. To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/43abcfed-edaa-6f05-04cc-f30a9b0e59e6%40oddbird.net. For more options, visit https://groups.google.com/d/optout.
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