Account/Transaction Spike

Quick spike to demonstrate how querying multiple account type and transaction types could work.

Setup and Running

Setup

npm install

Generate Data

There is already a set of data generated in accounts.json; this can be regenerated using the command npm run generate-accounts.

Run

npm start

Then visit the GraphQL Playground at http://localhost:4000/graphql (does not work in Safari, use Chrome)

Overview

There are two interfaces and several implementing types; review the schema to understand the interface and type definitions in more depth.

Account

Describes the common fields for any account. In this example these are:

• identifier - the account identifierd
• transactions - an array of Transaction types

There are two types implementing this interface: AccountVariantOne and AccountVariantTwo - each provide an additional field in addition to those specified by the core interface. These are oversimplified examples demonstrating that multiple implementing variants can be represented.

Transaction

Describes the common feilds for any transaction. In this example these are:

• id - the identifier of the transaction
• time - an ISO-8601 offset DateTime representation of the transaction time
• value - the value of the transaction

There are three types implementing this interface: TransactionVariantOne, TransactionVariantTwo and TransactionVariantThree - each provide an additional field in addition to those specified by the core interface. These are oversimplified examples demonstrating that multiple implementing variants can be represented.

Approach 1 - Unified Account/Transaction Querying

The optimal approach to query transactions for a given account is to query the graph as follows:

query {
  getAccount(accountIdentifier: "28388981") {
    ... on AccountVariantOne {
      actVariantOneField
    }
    # SHOWN TO DEMONSTRATE OMISSION
    # ... on AccountVariantTwo {
    #     actVariantTwoField
    # }
    transactions {
      time
      value
      ... on TransactionVariantOne {
        txnVariantOneField
      }
      ... on TransactionVariantTwo {
        txnVariantTwoField
      }
      # SHOWN TO DEMONSTRATE OMISSION
      # ... on TransactionVariantThree {
      # 	variantThreeField
      # }
    }
  }
}

This would retrieve time and value for each transaction, and also txnVariantOneField on transactions of variant one, txnVariantTwoField on transactions of variant two, and no additional data on transactions of variant three.

It would also retreive actVariantOneField for accounts of variant one, but no additional data on accounts of variant two.

The resulting data would look as follows:

{
  "data": {
    "getAccount": {
      "actVariantOneField": "Quis qui aliqua sint duis exercitation aute culpa nostrud.",
      "transactions": [
        {
          "time": "2021-08-11T08:33:08.721Z",
          "value": 9.73,
          "txnVariantOneField": "Anim reprehenderit ipsum esse enim nulla laboris labore incididunt."
        },
        ...
        {
          "time": "2021-03-28T04:59:36.558Z",
          "value": 135.66,
          "txnVariantTwoField": "Tempor ut dolor consequat proident culpa proident elit ullamco commodo nostrud commodo ullamco."
        },
        ...
        {
          "time": "2021-08-03T16:14:49.970Z",
          "value": 57.78
        },
        ...
      ]
    }
  }
}

Approach 2 - Query by Transaction Type

In this approach a consumer could request that only transaction types for a given account in a provided range are retrieved. The transactions would be split into buckets based on their type.

This is considered to be sub-optimal as it is counter to the simplicity of a graph hierarchy, and it is uncertain what use-case would justify such an approach.

An example query would be:

query {
  getAggregatedTransactions(
    accountIdentifier: "28388981"
    transactionTypes: [TRANSACTION_VARIANT_ONE, TRANSACTION_VARIANT_THREE]
  ) {
    type
    details {
      time
      value
      ... on TransactionVariantOne {
        txnVariantOneField
      }
      ... on TransactionVariantThree {
        txnVariantThreeField
      }
    }
  }
}

Resulting in the following data being returned:

{
  "data": {
    "getAggregatedTransactions": [
      {
        "type": "TRANSACTION_VARIANT_ONE",
        "details": [
          {
            "time": "2021-08-11T08:33:08.721Z",
            "value": 9.73,
            "txnVariantOneField": "Anim reprehenderit ipsum esse enim nulla laboris labore incididunt."
          },
          {
            "time": "2021-08-01T23:10:58.107Z",
            "value": 70.47,
            "txnVariantOneField": "Magna amet sint do ipsum deserunt veniam mollit."
          },
          ...
        ]
      },
      {
        "type": "TRANSACTION_VARIANT_THREE",
        "details": [
          {
            "time": "2021-08-03T16:14:49.970Z",
            "value": 57.78,
            "txnVariantThreeField": "Cillum proident sint amet nostrud ad labore qui anim dolor culpa adipisicing nulla."
          },
          {
            "time": "2021-03-15T08:33:06.571Z",
            "value": 45.91,
            "txnVariantThreeField": "Ullamco est adipisicing in anim veniam."
          },
          ...
        ]
      }
    ]
  }
}