That's great, Mike. I will help out on this and handle the below. I'll do
a Github ticket for tracking, and you can assign it to me.
On Thursday, July 25, 2019 at 9:44:10 PM UTC-4, Mike Bayer wrote:
>
>
>
> On Mon, Jul 22, 2019, at 10:51 PM, Jonathan Vanasco wrote:
>
>
>
> On Monday, July 22, 2019 at 9:36:10 PM UTC-4, Mike Bayer wrote:
>
>
> likely , the "create_constraint" flag should default to False for booleans
> and enums. I think it was a mistake to default these to true, I think
> people usually don't care.
>
>
> Everything you said was apparent to me, but I'm a seasoned SqlAlchemy
> user. I dove into the docs and didn't see warning dragons or anything that
> would suggest this happens alongside the Alembic or Boolean docs... this
> seemed like something that would trip up inexperienced users.
>
> I'm assuming I never saw this before on Postgres or MySql because sqlite
> requires a constraint to mimic boolean behaviors as there is no native
> type, but I usually reflect tables on those platforms so that could be the
> reason.
>
> Would it make sense to default the constraint name to something like
> "sa_autoname_xxxxx' where xxxx is a random hash?
>
>
> I would say no, because you are asking SQLAlchemy to make a guess a a name
> when the database would normally be doing this; however, that's not taking
> place since you've explicitly told it about a naming convention you'd like
> to use! if this naming convention should include "sa_autoname_xxxx" that
> should be explicit within the naming convention.
>
> this points to that, you probably don't want to be using
> %(constraint_name)s in your convention. Probably some other kind of token,
> like %({constraint_name:sa_autoname_12345})s or something, that is, some
> as-yet not defined feature to add to naming convention that allows
> constraint_name to have a fallback of some kind.
>
> However, you can make this feature yourself, as naming conventions allow
> custom callables:
>
>
> https://docs.sqlalchemy.org/en/13/core/constraints.html#constraint-naming-conventions
>
> it's near the end, and is a little weird in this case, but looks like:
>
> def auto_constraint_name(constraint, table):
> if constraint.name is None or constraint.name == "_unnamed_":
> return "sa_autoname_%s" % str(uuid.uuid4())[0:5]
> else:
> return constraint.name
>
> NAMING_CONVENTION = {
> "auto_constraint_name": auto_constraint_name,
> "ix": 'ix_%(column_0_label)s',
> "uq": "uq_%(table_name)s_%(column_0_name)s",
> "ck": "ck_%(table_name)s_%(auto_constraint_name)s",
> "fk": "fk_%(table_name)s_%(column_0_name)s_%(referred_table_name)s",
> "pk": "pk_%(table_name)s"
> }
> _metadata = sqlalchemy.MetaData(naming_convention=NAMING_CONVENTION)
>
>
> as always, this is not well documented, especially the weirdness with
> "_unnamed_" which is a default token of sorts, and if you have any time to
> help at all creating an example and/or working out use cases to make this
> easier for this as it should likely be the default for "ck", let me know.
>
>
>
>
>
>
>
>
>
>
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> SQLAlchemy -
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--
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http://www.sqlalchemy.org/
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