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Diffstat (limited to 'examples/asyncio/basic.py')
| -rw-r--r-- | examples/asyncio/basic.py | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/examples/asyncio/basic.py b/examples/asyncio/basic.py new file mode 100644 index 000000000..05cdd8a05 --- /dev/null +++ b/examples/asyncio/basic.py @@ -0,0 +1,71 @@ +"""Illustrates the asyncio engine / connection interface. + +In this example, we have an async engine created by +:func:`_engine.create_async_engine`. We then use it using await +within a coroutine. + +""" + + +import asyncio + +from sqlalchemy import Column +from sqlalchemy import Integer +from sqlalchemy import MetaData +from sqlalchemy import String +from sqlalchemy import Table +from sqlalchemy.ext.asyncio import create_async_engine + + +meta = MetaData() + +t1 = Table( + "t1", meta, Column("id", Integer, primary_key=True), Column("name", String) +) + + +async def async_main(): + # engine is an instance of AsyncEngine + engine = create_async_engine( + "postgresql+asyncpg://scott:tiger@localhost/test", echo=True, + ) + + # conn is an instance of AsyncConnection + async with engine.begin() as conn: + + # to support SQLAlchemy DDL methods as well as legacy functions, the + # AsyncConnection.run_sync() awaitable method will pass a "sync" + # version of the AsyncConnection object to any synchronous method, + # where synchronous IO calls will be transparently translated for + # await. + await conn.run_sync(meta.drop_all) + await conn.run_sync(meta.create_all) + + # for normal statement execution, a traditional "await execute()" + # pattern is used. + await conn.execute( + t1.insert(), [{"name": "some name 1"}, {"name": "some name 2"}] + ) + + async with engine.connect() as conn: + + # the default result object is the + # sqlalchemy.engine.Result object + result = await conn.execute(t1.select()) + + # the results are buffered so no await call is necessary + # for this case. + print(result.fetchall()) + + # for a streaming result that buffers only segments of the + # result at time, the AsyncConnection.stream() method is used. + # this returns a sqlalchemy.ext.asyncio.AsyncResult object. + async_result = await conn.stream(t1.select()) + + # this object supports async iteration and awaitable + # versions of methods like .all(), fetchmany(), etc. + async for row in async_result: + print(row) + + +asyncio.run(async_main()) |
