57 lines
1.5 KiB
Python
57 lines
1.5 KiB
Python
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"""Reusable column mixins.
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Pattern: subclass `Base, TimestampMixin, SoftDeleteMixin` to get the columns.
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"""
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from __future__ import annotations
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import uuid
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from datetime import datetime
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from sqlalchemy import DateTime, Uuid, func
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from sqlalchemy.orm import Mapped, mapped_column
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class UuidPkMixin:
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"""Native UUID primary key, generated Python-side."""
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id: Mapped[uuid.UUID] = mapped_column(
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Uuid(as_uuid=True),
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primary_key=True,
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default=uuid.uuid4,
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nullable=False,
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)
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class TimestampMixin:
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"""`created_at` / `updated_at` server-managed timestamps (UTC)."""
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created_at: Mapped[datetime] = mapped_column(
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DateTime(timezone=True),
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server_default=func.now(),
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nullable=False,
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)
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updated_at: Mapped[datetime] = mapped_column(
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DateTime(timezone=True),
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server_default=func.now(),
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onupdate=func.now(),
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nullable=False,
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)
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class SoftDeleteMixin:
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"""Soft delete via a nullable `deleted_at` column.
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NOTE: each soft-deletable model must declare its own `ix_<table>_active`
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partial index in `__table_args__`. We deliberately don't auto-inject one
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here because SQLAlchemy's `__table_args__` from a mixin gets clobbered as
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soon as the model class declares its own — silently dropping the index.
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Declaring it explicitly keeps the contract visible at the model site.
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"""
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deleted_at: Mapped[datetime | None] = mapped_column(
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DateTime(timezone=True),
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nullable=True,
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default=None,
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)
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