請注意，在 Cloud Firestore 中建構資料時，您有幾種不同的選項：
- 文件
- 多個集合
- 文件中的子集合
請根據您的用途，考量每個選項的優點。本指南列出階層式資料的幾個範例結構。
文件中的巢狀資料
您可以在文件中巢狀嵌入陣列或對映等複雜物件。
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子集合
如果資料可能會隨時間擴充，您可以在文件中建立集合。
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根層級集合
在資料庫的根層級建立集合，整理不同的資料集。
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選擇資料結構
除非另有註明，否則本頁面中的內容是採用創用 CC 姓名標示 4.0 授權，程式碼範例則為阿帕契 2.0 授權。詳情請參閱《Google Developers 網站政策》。Java 是 Oracle 和/或其關聯企業的註冊商標。
上次更新時間：2025-08-16 (世界標準時間)。
[null,null,["上次更新時間：2025-08-16 (世界標準時間)。"],[],[],null,["\u003cbr /\u003e\n\nRemember, when you structure your data in Cloud Firestore, you\nhave a few different options:\n\n- Documents\n- Multiple collections\n- Subcollections within documents\n\nConsider the advantages of each option as they\nrelate to your use case. A few example structures for hierarchical data\nare outlined in this guide.\n\n\u003cbr /\u003e\n\nNested data in documents\n\nYou can nest complex objects like arrays or maps within documents.\n\n|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------|\n| - **Advantages:** If you have simple, fixed lists of data that you want to keep within your documents, this is easy to set up and streamlines your data structure. - **Limitations:** This isn't as scalable as other options, especially if your data expands over time. With larger or growing lists, the document also grows, which can lead to slower document retrieval times. - **What's a possible use case?** In a chat app, for example, you might store a user's 3 most recently visited chat rooms as a nested list in their profile. | - class alovelace - name : first : \"Ada\" last : \"Lovelace\" born : 1815 rooms : 0 : \"Software Chat\" 1 : \"Famous Figures\" 2 : \"Famous SWEs\" |\n\nSubcollections\n\nYou can create collections within documents when you have data that might expand\nover time.\n\n|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| - **Advantages:** As your lists grow, the size of the parent document doesn't change. You also get full query capabilities on subcollections, and you can issue [collection group queries](../query-data/queries) across subcollections. - **Limitations:** You can't easily delete subcollections. - **What's a possible use case?** In the same chat app, for example, you might create collections of users or messages within chat room documents. | - collections_bookmark science - class software name : \"software chat\" - collections_bookmark users - class alovelace first : \"Ada\" last : \"Lovelace\" - class sride first : \"Sally\" last : \"Ride\"\\` \u003cbr /\u003e \u003cbr /\u003e - class astrophysics - ... |\n\nRoot-level collections\n\nCreate collections at the root level of your database to organize disparate data\nsets.\n\n|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| - **Advantages:** Root-level collections are good for many-to-many relationships and provide powerful querying within each collection. - **Limitations:** Getting data that is naturally hierarchical might become increasingly complex as your database grows. - **What's a possible use case?** In the same chat app, for example, you might create one collection for users and another for rooms and messages. | - collections_bookmark users - class alovelace first : \"Ada\" last : \"Lovelace\" born : 1815 - class sride first : \"Sally\" last : \"Ride\" born : 1951 - collections_bookmark rooms - class software - collections_bookmark messages - class message1 from : \"alovelace\" content : \"...\" - class message2 from : \"sride\" content : \"...\" |"]]