Copyright © 2022- basebox GmbH, all rights reserved.
Licensed to be used in conjunction with basebox, only.

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title = "@bb-scalar"

@bb_scalar

Define your own custom scalar (fundamental) type.

Syntax

Scalar:

scalar Identifier @bb_scalar(_type: ScalarType )

ScalarType:

Type: String
Values: Int | Float | String | ID | Boolean | Date | DateTime | Base64 | Void

Notes

@bb_scalar allows you to define your own custom scalar types. You might want to do this to indicate logical meaning to your scalar types. For example, instead of an integer for number of days i.e. GraphQL scalar type Int, you create a new type called NoOfDays defined like this:

scalar NoOfDays @bb_scalar(_type: "Int")

This new scalar type can then be used in any field that indicates number of days or as a return value for an operation that returns the number of days of any period (for example).

The values of the @bb_scalar directive _type argument correspond to either the built-in GraphQL scalar types or to specific scalar types that basebox has built (we will continually be extending this type). These types also correspond to Postgres data types as well. The following table indicates all the scalar types available for usage in the @bb_scalar directive's _type argument as well as the corresponding PostgreSQL types:

GraphQL	PostgreSQL
Int	INTEGER
Float	FLOAT8
String	VARCHAR
Boolean	BOOLEAN
ID	UUID
Date	DATE
DateTime	TIMESTAMP
Base64	BYTEA
Void	no equivalent

Void is a special type that does not have a PostgreSQL equivalent. It is used to indicate that an operation does not return any values and cannot be used to define a field but only as an operation return value.

Examples

DateTime Example

scalar Date @bb_scalar(_type: "Date")

type Patient {
  id: ID!
  name: String
  dateOfBirth: Date
}

In the above example, we declare a Date scalar type and use it to create a date of birth field of type Date.

Base64 Example

scalar Document @bb_scalar(_type: "Base64")

type PatientDocuments {
  id: ID!
  patient: Patient
  document: Document
}

Here we create a scalar type called Document and use it to store patient documents in binary format.

Void Example

scalar Void @bb_scalar(_type: "Void")

type Patient {
  id: ID!
  name: String
  dateOfBirth: Date
}

mutation {

  # insert a new patient record
  insertPatient(
    id: ID!
    name: String!
    dateOfBirth: Date
  ): Patient

  # update an existing patient record
  updatePatient(
    id: ID!
    name: String!
    dateOfBirth: Date
  ): Void

}

We've created a Void scalar type and used it to create an update for patient record. The update to the Patient will not return any data. Contrast this to the insertPatient mutation created, this returns a Patient record and you would have to specify the patient fields that you want to return when calling this mutation.