SQLAlchemy cannot use `__table_args__` to set schema related configuration and index at the same time?

Question

Here is my base class for Model:

@declarative_mixin
class FixtureMixin:
    __table_args__ = {
        "mysql_engine": "InnoDB",
        "mysql_charset": "utf8",
        "extend_existing": True,
    }
    pass

For subclasses, I want to be able to configure the index in __table_args__ while retaining the public configuration, like this:

class TestTable(db.Model, FixtureMixin):
    __tablename__ = "test_table"

    __table_args__ = FixtureMixin.__table_args__.copy()
    __table_args__.update({
        "schema": "test",
        "comment": "xxx",
        "mysql_indexes": [Index('unique_org_test_key', "name", "org_id", unique=True)]
    })
    pass

However, when I create_all, it does not work as expected. What should I do if I want to achieve the expected effect?

Answer 1

Combine parameters and change the way parameters are passed, just like:

class TestTable(db.Model, FixtureMixin):
    __tablename__ = "test_table"
    __table_args__ = (
        db.UniqueConstraint("name", name="unique_org_test_key"),
        dict(
            **FixtureMixin.__table_args__,
            schema="test",
            comment="xxx"
        )
    )

or:

class TestTable(db.Model, FixtureMixin):
    __tablename__ = "test_table"

    @declared_attr
    def __table_args__(cls):
        table_args = FixtureMixin.__table_args__.copy()
        table_args.update(
            schema="test",
            comment="xxx",
        )
        table_args = (
            db.Index('unique_org_test_key', 'name'),
            table_args,
        )
        return table_args