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Is there a way to get a list of keys of all child nodes (either once or with an open connection), without transferring all the data for those child nodes?

Linda H
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1 Answers1

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The Firebase JavaScript SDK always retrieves complete nodes, so there is no way to read only the keys.

The Firebase REST API has a parameter shallow=true that will retrieve only the keys under the location. See https://firebase.google.com/docs/database/rest/retrieve-data#shallow

If you don't want to use the REST API, you'll have to restructure your data to allow for the query you want. It is quite common in NoSQL data stores to maintain you own indexes, just for such queries.

E.g.

/users
  "12-ad-b3-ad"
    name: "Frank van Puffelen"
    stackoverflowId: 209103
    bio: "auihodasiuodsa ohdsau duia hdsauhio aoi das"
    avatarUrl: "https://www.gravatar.com/avatar/12d378e6a9788ab9c94bbafe242b82b4?s=48&d=identicon&r=PG"
  "18-a7-12-86"
    name: "Linda H"
    stackoverflowId: 3243018
    bio: "as ihuew rew i noiueh ewo we weru irew ure oew"
    avatarUrl: "https://i.stack.imgur.com/0lcm6.jpg?s=32&g=1"
/uids
  "12-ad-b3-ad": true
  "18-a7-12-86": true
/stackoverflowIds
  209103: "12-ad-b3-ad"
  3243018: "18-a7-12-86"
Frank van Puffelen
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    Thanks for the info. I may have to mix REST with the JS SDK as I'd like to keep denormalization/duplication to a minimum. – Linda H Sep 07 '15 at 17:05
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    The REST implementation on that page has been deprecated - is there a supported way to do it today? – fmacdee Mar 13 '17 at 22:45