BigInt fields

GraphQL objects types have names and fields, but at the end of the day, these fields will either have to be other object types, or resolve to some concrete data. This concrete data is represented by Scalar types. GraphQL comes with its own default set of Scalar types, but different implementations can define their own.

As part of OpenReader, we have developed the BigInt Scalar type. This field allows storing much larger numbers than the commonly used Int.

Typical Int fields are 4 bytes (32 bit) signed integers, which are able to represent numbers between -2147483648 and +2147483648. The BigInt scalar type defined in a schema will be mapped to the numeric field when creating the SQL table and this field is able to accommodate up to 131072 digits.

A schema defined as such:

schema.graphql

type Account @entity {
  "Account address"
  id: ID!
  balance: BigInt!
  historicalBalances: [HistoricalBalance!] @derivedFrom(field: "account")
}

type HistoricalBalance @entity {
  id: ID!
  account: Account!
  balance: BigInt!
  date: DateTime!
}

Will result in these tables being created:

create table account (id text primary key, balance numeric)`,
create table historical_balance (id text primary key, account_id text references account(id), balance numeric, date timestamp)

And both balance fields will be able to store numbers like 2000000000000000000000000000000000000 and much larger.