Nested field queries

Overview

With OpenReader, fields of an Entity that contain fields themselves are shown as nested fields and it is possible to filter these as well. GraphQL queries can traverse related objects and their fields, letting clients fetch lots of related data in one request, instead of making several roundtrips as one would need in a classic REST architecture.

As an example, this query searches for all accounts whose balance is bigger than a threshold value, fetching the id, balance simple fields, and the historicalBalances nested field.

query {
  accounts(orderBy: balance_ASC, where: {balance_gte: "250000000000000000"}) {
    id
    balance
    historicalBalances {
      balance
      date
      id
    }
  }
}

The nested field is a list (one account can have multiple historicalBalances) of objects with fields of their own and these results are filtered, in turn.

In this query, the historicalBalances are filtered, so that only results created after a certain date are returned

query {
  accounts(orderBy: balance_ASC, where: {balance_gte: "250000000000000000"}) {
    id
    balance
    historicalBalances(where: {date_lte: "2020-10-31T11:59:59.000Z"}, orderBy: balance_DESC) {
      balance
      date
      id
    }
  }
}