count()

Get the number of values in a Set.

Signature

count(): Int

Description

The count() method gets the number of values in the Set.

Because this method scans the full set, the query can time out for large sets.

A document update stores a new version of the document for which counter data is poorly suited for database storage.

If a frequently updated counter is essential, an event-sourcing technique is recommended to reduce database contention and reduce unnecessary database operations.

If the event sourcing pattern isn’t suitable, the following improvements might be considered:

  • Set a collection history_days field to a small value, with a zero value recommended. Document history continues to be collected, but is removed sooner than the default zero days.

  • Periodically, run a query to explicitly remove document history.

  • Instead of attempting to implement a real-time counter, consider storing countable documents as a cache and periodically analyzing cache contents to update a reporting document.

Parameters

None

Return value

Type Description

Int

Count of values in the Set.

Examples

Get the number of books in the Book collection.

  1. List the Book documents:

    Books.all()
    {
  data: [
    {
      id: "358933729814511650",
      coll: Books,
      ts: Time("2023-03-11T19:58:49.450Z")
      name": "Book of Ond",
    },
    {
      id: "358933733773934626",
      coll: Books,
      ts: Time("2023-03-11T19:58:53.220Z")
      name: "Book of Two",
    },
    {
      id: "365634774532882466",
      coll: Books,
      ts: Time("2023-05-24T19:52:42.340Z"),
      name: "Book of Three",
    }
  ]
}

  2. Get a count of the number of documents:

    Books.all().count()
    3

 

Count the Customers documents where the state property is DC:

Customer.where(.address.state == 'DC').count()
3

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