Hello everyone,
I wanted to follow up on the examples on Composite Column Types
<https://docs.sqlalchemy.org/en/20/orm/composites.html> and in particular
setting the mapped composite value in Python-land to *None*.
For instance, this class
@dataclasses.dataclass
class Point:
x: int
y: int
is used in the following composite mapping and I’d like the two mapped
properties to be optional (for the sake of the argument, whether it makes
sense or not):
class Vertex(Base):
start: Mapped[Point] | None = composite(mapped_column("x1"),
mapped_column("y1"))
end: Mapped[Point] | None = composite(mapped_column("x2"), mapped_column
("y2"))The optional would then have to map to *nullable=True* for both
mapped columns, which in turn would need to be checked to ensure integrity
— either both or neither of the two mapped columns for a *Point* can be
NULL at the same time.
I wasn’t able to find a recipe
<https://docs.sqlalchemy.org/en/20/orm/examples.html> for this use case.
What’s the recommendation to implement this? Will I have to roll most of
this manually, or does SQLA provide support?
Much thanks!
Jens
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