CODEWITHSUNDEEP
databasecouchdb
PablodeAcero
PablodeAcero

Reputation: 411

Fetch partial documents from couchdb

I'm using couchdb to store large documents, which is causing some trouble when fetching them to memory. I do realize the database is not meant to be used this way. As a fallback solution, is it possible to fetch partial documents from the database, without creating a view?

In example, if a document has the fields id, content and extra_content, I would like to retrieve only the first two.

Thank you in advance.

Upvotes: 1

Views: 754

Answers (2)

Jonathan Hall
Jonathan Hall

Reputation: 79744

This is not possible prior to CouchDB 2.x. For CouchDB 2.x or greater, see JuanjoRodriguez's answer.

But one possible work around for any version of CouchDB would be to take advantage of file attachments, which by default are excluded from a fetch. If some of your data isn't always needed, and doesn't need to be included in indexes, you could potentially store it as (JSON) attachments, rather than as part of the document directly:

{
    "id": "foo",
    "content": "stuff",
    "extra_content": "other stuff"
}

becomes:

{
    "id": "foo",
    "content": "stuff",
    "_attachments": {
        "extra_content": {
            "content_type": "application/json",
            "data": "ZXh0cmEgc3R1ZmYK"
        }
    }
}

Upvotes: 1

Juanjo Rodriguez
Juanjo Rodriguez

Reputation: 2131

If you are using CouchDB 2.x, you can use /db/_find endpoint as a mechanism to retrieve part of the doc.

POST /db/_find

  {
    "selector": {
      "_id": "a-doc-id"
    },
    "fields": [
      "_id",
      "content"
    ]
   }

You'll get only the set of fields you have specified in the query

Upvotes: 4

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