如何将原始 SQL 查询转换为 gino ORM 查询？

Question

我在 postgreSQL 数据库中安装并启用了 postGIS 扩展程序。

                                         Table "public.crime_data"


   Column    |            Type             | Collation | Nullable |                Default                 
-------------|-----------------------------|-----------|----------|----------------------------------------
 id          | integer                     |           | not null | nextval('crime_data_id_seq'::regclass)
 state       | character varying           |           |          | 
 district    | character varying           |           |          | 
 location    | character varying           |           |          | 
 sub_type_id | integer                     |           |          | 
 date_time   | timestamp without time zone |           |          | 
 latitude    | double precision            |           |          | 
 longitude   | double precision            |           |          | 
 geom_point  | geography(Point,4326)       |           |          | 


Indexes:
    "crime_data_pkey" PRIMARY KEY, btree (id)
    "idx_crime_data_geom_point" gist (geom_point)
Foreign-key constraints:
    "crime_data_sub_type_id_fkey" FOREIGN KEY (sub_type_id) REFERENCES sub_type(id)

我正在使用 Sanic 网络框架和 Gino ORM，因为它是异步的。

我可以在命令行中编写和运行原始 SQL 查询，也可以使用Gino。我只是想知道是否可以将某个查询转换为 ORM 语法。

这是工作的原始查询。这段代码 sn-p 在一个异步视图函数中，它返回了预期的结果。

data_points = await db.status(db.text('''
    SELECT 
        location, 
        sub_type_id, 
        latitude, 
        longitude, 
        date_time
    FROM 
        crime_data
    WHERE 
        ST_Distance(
        geom_point,
        ST_SetSRID(ST_MakePoint(:lng, :lat), 4326)
    ) <= 5 * 1609.34;
'''), {
    'lat': lat,
    'lng': lng,
})

这是我尝试将其转换为 ORM 查询，不工作。

data_points = await CrimeData.query.where(
    geo_func.ST_Distance(
        'geom_point',
        geo_func.ST_SetSRID(
            geo_func.ST_MakePoint(lng, lat),
            4326
        )
    ) <= (5 * 1609.34)
).gino.all()

在尝试运行此查询并将响应返回为 text 时，我收到此错误。

⚠️ 500 — Internal Server Error
parse error - invalid geometry HINT: "ge" <-- parse error at position 2 within geometry

Traceback of __main__ (most recent call last):
InternalServerError: parse error - invalid geometry HINT: "ge" <-- parse error at position 2 within geometry
File /home/disciple/Documents/Code/MyProject-All/MyProject-Sanic/venv/lib/python3.8/site-packages/sanic/app.py, line 973, in handle_request

response = await response

File /home/disciple/Documents/Code/MyProject-All/MyProject-Sanic/backend/services/crime_plot.py, line 30, in test

data_points = await CrimeData.query.where(

File /home/disciple/Documents/Code/MyProject-All/MyProject-Sanic/venv/lib/python3.8/site-packages/gino/api.py, line 127, in all

return await self._query.bind.all(self._query, *multiparams, **params)

File /home/disciple/Documents/Code/MyProject-All/MyProject-Sanic/venv/lib/python3.8/site-packages/gino/engine.py, line 740, in all

return await conn.all(clause, *multiparams, **params)

File /home/disciple/Documents/Code/MyProject-All/MyProject-Sanic/venv/lib/python3.8/site-packages/gino/engine.py, line 316, in all

return await result.execute()

File /home/disciple/Documents/Code/MyProject-All/MyProject-Sanic/venv/lib/python3.8/site-packages/gino/dialects/base.py, line 214, in execute

rows = await cursor.async_execute(

File /home/disciple/Documents/Code/MyProject-All/MyProject-Sanic/venv/lib/python3.8/site-packages/gino/dialects/asyncpg.py, line 184, in async_execute

result, stmt = await getattr(conn, "_do_execute")(query, executor, timeout)

File /home/disciple/Documents/Code/MyProject-All/MyProject-Sanic/venv/lib/python3.8/site-packages/asyncpg/connection.py, line 1433, in _do_execute

result = await executor(stmt, None)

File asyncpg/protocol/protocol.pyx, line 196, in bind_execute


InternalServerError: parse error - invalid geometry HINT: "ge" <-- parse error at position 2 within geometry while handling path /crime-plot/test1

我了解 ORM 查询是 SELECT *，只要我真正得到结果就可以了。我不明白我做错了什么。我正在完成工作，但我只是想确保 ORM 也可以。

这是相关的视图函数的代码。

@app.route('/test')
async def test(request):
    """
    /test?lng=88.21927070000001&lat=23.9130464
    """
    lat = request.args.get('lat')
    lng = request.args.get('lng')
    if lat and lng:
        lat = float(lat)
        lng = float(lng)

        data_points = ...  # either of the above mentioned queries
        return text(data_points)
    else:
        return text('ERROR: lat or lng value missing')

Answer 1

由于您使用的是 ORM，因此您需要使用模型类的属性而不是字符串作为列名。将 ORM 查询更改为此，它应该可以工作。

data_points = await CrimeData.query.where(
    geo_func.ST_Distance(
        CrimeData.geom_point,
        geo_func.ST_SetSRID(
            geo_func.ST_MakePoint(lng, lat),
            4326
        )
    ) <= (5 * 1609.34)
).gino.all()