79 lines
2.0 KiB
Python
79 lines
2.0 KiB
Python
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import asyncio
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import sqlalchemy
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from sqlalchemy import orm as sqlalchemy_orm
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from sqlalchemy import future as sqlalchemy_future
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from Database.base import Base
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from Database.database import Database
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class A(Base):
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__tablename__ = "a"
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data = sqlalchemy.Column(sqlalchemy.String)
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create_date = sqlalchemy.Column(sqlalchemy.DateTime, server_default=sqlalchemy.func.now())
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bs = sqlalchemy_orm.relationship("B")
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# required in order to access columns with server defaults
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# or SQL expression defaults, subsequent to a flush, without
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# triggering an expired load
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__mapper_args__ = {"eager_defaults": True}
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class B(Base):
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__tablename__ = "b"
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a_id = sqlalchemy.Column(sqlalchemy.ForeignKey("a.id"))
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data = sqlalchemy.Column(sqlalchemy.String)
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async def main():
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db = Database(
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"postgresql://localhost:5432/testing",
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)
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await db.drop_all()
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await db.create_all()
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# expire_on_commit=False will prevent attributes from being expired
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# after commit.
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async with db.async_session() as session:
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async with session.begin():
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session.add_all(
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[
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A(bs=[B(), B()], data="a1"),
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A(bs=[B()], data="a2"),
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A(bs=[B(), B()], data="a3"),
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]
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)
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stmt = sqlalchemy_future.select(A).options(sqlalchemy_orm.selectinload(A.bs))
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result = await session.execute(stmt)
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for a1 in result.scalars():
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print(a1)
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print(f"created at: {a1.create_date}")
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for b1 in a1.bs:
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print(b1)
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result = await session.execute(sqlalchemy_future.select(A).order_by(A.id))
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a1 = result.scalars().first()
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a1.data = "new data"
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await session.commit()
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# access attribute subsequent to commit; this is what
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# expire_on_commit=False allows
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print(a1.data)
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# for AsyncEngine created in function scope, close and
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# clean-up pooled connections
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await db.async_engine.dispose()
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asyncio.run(main())
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