查询 Firestore 集合(异步)
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查询 Firestore 集合(异步)。
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[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],[],[[["\u003cp\u003eThis code sample demonstrates how to query a Firestore collection asynchronously using Python.\u003c/p\u003e\n"],["\u003cp\u003eThe example code utilizes \u003ccode\u003estream()\u003c/code\u003e to retrieve documents, which is the preferred method over \u003ccode\u003eget()\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe query filters data in the "cities" collection to only include documents where the "capital" field is true.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication is needed to access the Firestore database, and it uses the Application Default Credentials, for which further setup instructions are available.\u003c/p\u003e\n"]]],[],null,["# Query a Firestore collection (async).\n\nExplore further\n---------------\n\n\nFor detailed documentation that includes this code sample, see the following:\n\n- [Get data with Cloud Firestore](https://firebase.google.com/docs/firestore/query-data/get-data)\n- [Getting data](/firestore/native/docs/query-data/get-data)\n- [Perform simple and compound queries in Cloud Firestore](https://firebase.google.com/docs/firestore/query-data/queries)\n- [Query and filter data](/firestore/native/docs/query-data/queries)\n\nCode sample\n-----------\n\n### Python\n\n\nTo authenticate to Firestore, set up Application Default Credentials.\nFor more information, see\n\n[Set up authentication for a local development environment](/docs/authentication/set-up-adc-local-dev-environment).\n\n # Note: Use of CollectionRef stream() is prefered to get()\n docs = (\n db.collection(\"cities\")\n .where(filter=FieldFilter(\"capital\", \"==\", True))\n .stream()\n )\n\n async for doc in docs:\n print(f\"{doc.id} =\u003e {doc.to_dict()}\")\n\nWhat's next\n-----------\n\n\nTo search and filter code samples for other Google Cloud products, see the\n[Google Cloud sample browser](/docs/samples?product=firestore)."]]