我正在尝试在pyDAL中执行此MongoDB的搜索查询：
db.stores.find({
'menu.items.food.category': 'Pizza'
})
商店集合到pyDAL表的映射为：
Store = db.define_table(
'stores',
Field('name'),
Field('date', type='datetime'),
Field('description', type='json'),
Field('address'),
Field('featured', type='boolean'),
Field('lat', type='double'),
Field('lng', type='double'),
Field('image'),
Field('city'),
Field('menu', type='json'),
Field('country'),
Field('category'),
Field('URI'),
Field('reviews', type='list:string')
)
我在做：
第一次尝试：
db(Store.menu.items.food.category == 'Pizza').select())
输出：
Traceback (most recent call last):
File "/home/mmagni/www/appicar/qa-automation/main.py", line 6, in <module>
print(db(Store.menu.items.food.category == 'Pizza').select())
AttributeError: 'Field' object has no attribute 'items'
第二次尝试：
db(Store.menu['items']['food']['category'] == 'Pizza').select()
输出：
Traceback (most recent call last):
File "/home/mmagni/www/appicar/qa-automation/main.py", line 6, in <module>
print(db(Store.menu['items']['food']['category'] == 'Pizza').select())
File "/usr/local/lib/python3.6/dist-packages/pydal/objects.py", line 1338, in __getitem__
return self[i:i + 1]
TypeError: must be str, not int
最后，我试图带上具有菜单的商店：
for store in db(Store.menu).select():
pprint(store.as_dict())
输出：
/usr/bin/python3.6 /home/mmagni/www/appicar/qa-automation/main.py
{'URI': 'lerot',
'address': 'Av. Arístides Villanueva 263',
'category': 'DB.bar-restaurant',
'city': 'Mendoza',
'country': 'Argentina',
'date': datetime.datetime(2017, 8, 5, 1, 29, 52, 789000),
'description': {'en': 'A friendly place, where you feel comfortable and at '
'home is what matters to us. Attended by its owners, '
'the most important thing is that you eat and drink for '
'a very convenient price. What you can not stop eating '
'are the "LeRot Fries", a classic of our place. We '
'expect you! Closing time: you define it. Food: the '
'tastiest and most economical of the street. Drinks: '
'our bartender prepares you whatever you want. If you '
'say you found us on TripAdvisor, you have a 15% '
'discount on your account.',
'es': 'Un lugar amigable, donde sentirte cómodo y como en '
'casa es lo que nos importa. Atendido por sus dueños , '
'lo más importante es que comés y tomás por un precio '
'muy conveniente. Lo que no podés dejar de comer son '
'las “Papas LeRot", un clásico de nuestro lugar ¡Te '
'esperamos! Hora de cierre: la ponés vos. Comida: la '
'más rica y económica de la calle. Tragos: nuestro '
'bartender te prepara lo que vos quieras. Si decís que '
'nos encontraste en TripAdvisor, tenés un 15% de '
'descuento en tu cuenta.',
'it': 'Un luogo accogliente, dove ti senti a tuo agio e a '
'casa è ciò che conta per noi. Frequentato dai suoi '
'proprietari, la cosa più importante è che mangi e bevi '
'per un prezzo molto conveniente. Quello che non puoi '
'smettere di mangiare sono le "LeRot Fries", un '
'classico del nostro locale. Vi aspettiamo! Tempo di '
'chiusura: lo definisci. Cibo: il più gustoso e più '
'economico della strada. Bevande: il nostro barista ti '
'prepara tutto ciò che vuoi. Se dici che ci hai trovato '
'su TripAdvisor, hai uno sconto del 15% sul tuo '
'account.'},
'featured': True,
'id': 28202411502443212115215594329,
'image': 'http://cdn.appicar.com/stores/ZPoYEMmanZgmFvYpC.jpg',
'lat': -32.8923525,
'lng': -68.8540556,
'menu': {'items': {'drink': [{'_id': ObjectId('5aa06d7784b554537f88885a'),
'category': 'Drinks with Alcohol',
'date': datetime.datetime(2018, 3, 6, 2, 21, 4, 958000),
'name': {'en': 'Fernet with Coke to prepare',
'es': 'Fernet con Coca para preparar',
'it': 'Fernet con Coca-Cola da '
'preparare'},
'paymentMethods': ['Cash', 'Credit Card'],
'picture': 'http://cdn.appicar.com/stores/menu/ZPoYEMmanZgmFvYpC/5aa06d7784b554537f88885a.jpg',
'price': [{'currency': 'ARS', 'value': 120.0}]}],
'food': [{'_id': ObjectId('5aa06d7784b554537f888858'),
'category': 'Pizza',
'date': datetime.datetime(2018, 3, 6, 2, 21, 4, 958000),
'name': {'en': 'Mozzarella pizza',
'es': 'Pizza Mozzarella',
'it': 'Pizza alla Mozzarella'},
'paymentMethods': ['Cash', 'Credit Card'],
'picture': 'http://cdn.appicar.com/stores/menu/ZPoYEMmanZgmFvYpC/5aa06d7784b554537f888858.jpg',
'price': [{'currency': 'ARS', 'value': 150.0}]},
{'_id': ObjectId('5aa06d7784b554537f888859'),
'category': 'Lomito',
'date': datetime.datetime(2018, 3, 6, 2, 21, 4, 958000),
'name': {'en': 'Provolone Sandwich',
'es': 'Provolomo',
'it': 'Panino al Provolone'},
'paymentMethods': ['Cash', 'Credit Card'],
'picture': 'http://cdn.appicar.com/stores/menu/ZPoYEMmanZgmFvYpC/5aa06d7784b554537f888859.png',
'price': [{'currency': 'ARS',
'value': 180.0}]}]}},
'name': 'LeRot',
'reviews': [{'_id': ObjectId('5aa943ea602e8b6921d0bb66'),
'clientId': 'TGTbYMoThGpZWveKa',
'clientName': 'Matías J. Magni',
'clientPicture': 'http://cdn.appicar.com/users/TGTbYMoThGpZWveKa.png',
'date': datetime.datetime(2018, 3, 14, 15, 46, 50, 497000),
'points': 4.0,
'text': {'en': 'Excellent place, the drinks are amazing and they '
'serve squid rings!',
'es': 'Excelente lugar, los tragos son muy ricos y '
'¡sirven rabas!',
'it': 'Posto eccellente, le bevande sono molto gustose '
'e servono anelli di calamari!'}},
{'_id': ObjectId('5aaacf349304c432ef2bbe4b'),
'clientId': 'GnLdeKy6kmDhAkAkF',
'clientName': 'Edgardo Marti',
'clientPicture': 'http://cdn.appicar.com/users/GnLdeKy6kmDhAkAkF.jpg',
'date': datetime.datetime(2018, 3, 15, 19, 53, 24, 633000),
'points': 3.0,
'text': {'en': 'Very nice place to spend a quiet time with your '
'mate. Very affordable prices and good attention '
'from the waiters.',
'es': 'Lindo lugar para pasar un rato tranquilo con tu '
'pareja. Los precios muy asequibles y buena '
'atención por parte de los mozos.',
'it': 'Bello posto per trascorrere un periodo '
'tranquillo con il tuo compagno. Prezzi molto '
'convenienti e buona attenzione da parte dei '
'camerieri.'}}]}
{'URI': 'antares',
'address': 'Av. Arístides Villanueva 153',
'category': 'DB.bar',
'city': 'Mendoza',
'country': 'Argentina',
'date': datetime.datetime(2017, 8, 5, 1, 51, 35, 847000),
'description': {'en': 'Antares is an Argentine brewery that produces craft '
'beers in the city of Mar del Plata since 1998. It is '
'made in seven varieties, following European recipes, '
'not only found in the Argentine market, but it is '
'already marketed in Brazil, Canada, United States, '
'Uruguay and Sweden, exports involve a little more than '
'20,000 bottles per year. Some of the varieties are '
'aged in oak vases for a month, achieving unique '
'flavors and an alcoholic strength of 8%. Locations '
'have been installed in different Argentine provinces '
'and in Buenos Aires, where you can taste some '
'appetizers, dishes of German food and the seven '
'varieties of beer they make. The production is 50,000 '
'liters of beer per month. We assign tables by arrival. '
'Antares bottle loading every day from 18 a 21 hs. ',
'es': '',
'it': ''},
'featured': True,
'id': 28202411502443212115215594330,
'image': 'http://cdn.appicar.com/stores/5kPxqXmRw6yyjfRLb.jpg',
'lat': -32.892855,
'lng': -68.851691,
'menu': {'items': {'food': [{'_id': ObjectId('5aa06c7a84b554537f888855'),
'category': 'Pizza',
'date': datetime.datetime(2018, 3, 7, 22, 49, 30, 118000),
'name': {'en': 'Mozzarella Pizza',
'es': 'Pizza Mozzarella',
'it': 'Pizza alla Mozzarella'},
'paymentMethods': ['Cash', 'Credit Card'],
'picture': 'http://cdn.appicar.com/stores/menu/5kPxqXmRw6yyjfRLb/5aa06c7a84b554537f888855.jpg',
'price': [{'currency': 'ARS',
'value': 120.0}]}]}},
'name': 'Antares',
'reviews': [{'_id': ObjectId('5aaad09e9304c432ef2bbe4f'),
'clientId': 'TGTbYMoThGpZWveKa',
'clientName': 'Matías J. Magni',
'clientPicture': 'http://cdn.appicar.com/users/TGTbYMoThGpZWveKa.png',
'date': datetime.datetime(2018, 3, 14, 15, 46, 50, 497000),
'points': 2.0,
'text': {'en': 'Excellent place to spend a quiet time with your '
'mate. Very affordable prices and good attention '
'from the waiters.',
'es': 'Excelente lugar para pasar un rato tranquilo con '
'tu pareja. Los precios muy asequibles y buena '
'atención por parte de los mozos.',
'it': 'Posto eccellente per trascorrere un periodo '
'tranquillo con il tuo compagno. Prezzi molto '
'convenienti e buona attenzione da parte dei '
'camerieri.'}},
{'_id': ObjectId('5aaad09e9304c432ef2bbe50'),
'clientId': 'GnLdeKy6kmDhAkAkF',
'clientName': 'Edgardo Marti',
'clientPicture': 'http://cdn.appicar.com/users/TGTbYMoThGpZWveKa.png',
'date': datetime.datetime(2018, 3, 15, 19, 53, 24, 633000),
'points': 4.0,
'text': {'en': 'Excellent place to spend a quiet time with your '
'mate. Very affordable prices and good attention '
'from the waiters.',
'es': 'Excelente lugar para pasar un rato tranquilo con '
'tu pareja. Los precios muy asequibles y buena '
'atención por parte de los mozos.',
'it': 'Posto eccellente per trascorrere un periodo '
'tranquillo con il tuo compagno. Prezzi molto '
'convenienti e buona attenzione da parte dei '
'camerieri.'}}]}
商店。菜单 字段定义为 JSON 。如何在其键内执行查询？
答案 0 :(得分：2)
pyDAL可以在任何数据库中存储 JSON数据，但是即使在支持此类操作的数据库中，它也没有用于查询的API。如果使用支持SQL的数据库（例如Postgres），则可以通过将原始SQL字符串作为查询传递给DAL对象来在JSON字段中进行查询。但是，这种方法不适用于MongoDB。
对于MongoDB，最好的方法是直接使用pymongo驱动程序进行查询。您可以通过pymongo创建自己的连接，也可以重新使用pyDAL创建的连接，可以在db._adapter.connection上进行访问（驱动程序本身可以在db._adapter.driver上进行访问）。
答案 1 :(得分：0)
您将JSON视为对象-在JS中可以，但在Python中则可以。标准Python没有JSON对象的概念-在Python中，JSON只是字典和列表的分层混合，所以
Store['menu']['items']['food'][0]['category']
会给你'Pizza'
答案 2 :(得分：0)
我可以执行类似操作的唯一方法是首先找到菜单不是 null 的商店，然后通过pyDAL过滤映射到 dict 的JSON字段：< / p>
stores = db(Store.menu).select()
results = []
for store in stores:
results.append(list(filter(lambda food: food['category'] == 'Pizza', store.menu['items']['food'])))
pprint(results)
输出：
[[{'_id': ObjectId('5aa06d7784b554537f888858'),
'category': 'Pizza',
'date': datetime.datetime(2018, 3, 6, 2, 21, 4, 958000),
'name': {'en': 'Mozzarella pizza',
'es': 'Pizza Mozzarella',
'it': 'Pizza alla Mozzarella'},
'paymentMethods': ['Cash', 'Credit Card'],
'picture': 'http://cdn.appicar.com/stores/menu/ZPoYEMmanZgmFvYpC/5aa06d7784b554537f888858.jpg',
'price': [{'currency': 'ARS', 'value': 150.0}]}],
[{'_id': ObjectId('5aa06c7a84b554537f888855'),
'category': 'Pizza',
'date': datetime.datetime(2018, 3, 7, 22, 49, 30, 118000),
'name': {'en': 'Mozzarella Pizza',
'es': 'Pizza Mozzarella',
'it': 'Pizza alla Mozzarella'},
'paymentMethods': ['Cash', 'Credit Card'],
'picture': 'http://cdn.appicar.com/stores/menu/5kPxqXmRw6yyjfRLb/5aa06c7a84b554537f888855.jpg',
'price': [{'currency': 'ARS', 'value': 120.0}]}]]