XDM field type constraints

In Experience Data Model (XDM) schemas, a field’s type constrains what kind of data the field can contain. This document provides an overview of each core field type, including the other serialization formats they can be mapped to and how to define your own field types in the API in order to enforce different constraints.

Getting started

Before using this guide, please review the basics of schema composition for an introduction to XDM schemas, classes, and schema field groups.

If you plan on defining your own field types in the API, it is strongly recommended that you start with the Schema Registry developer guide to learn how to create field groups and data types to include your custom fields in. If you are using the Experience Platform UI to create your schemas, see the guide on defining fields in the UI to learn how implement constraints on fields that you define within custom field groups and data types.

Base structure and examples

XDM is built on top of JSON Schema, and therefore XDM fields inherit a similar syntax when defining their type. Understanding how different field types are represented in JSON Schema can help indicate the base constraints of each type.

The following table outlines how each XDM type is represented in JSON Schema, along with an example value that conforms to the type:

{"type": "string"}

{"type": "number"}

{
  "type": "integer",
  "maximum": 9007199254740991,
  "minimum": -9007199254740991
}

{
  "type": "integer",
  "maximum": 2147483648,
  "minimum": -2147483648
}

{
  "type": "integer",
  "maximum": 32768,
  "minimum": -32768
}

{
  "type": "integer",
  "maximum": 128,
  "minimum": -128
}

{
  "type": "string",
  "format": "date"
}

{
  "type": "string",
  "format": "date-time"
}

{"type": "string"}

*All date-formatted strings must conform to the ISO 8601 standard (RFC 3339, section 5.6).

Mapping XDM types to other formats

The sections below describe how each XDM type maps to other common serialization formats:

• Parquet, Spark SQL, and Java
• Scala, .NET, and CosmosDB
• MongoDB, Aerospike, and Protobuf 2

Parquet, Spark SQL, and Java

Scala, .NET, and CosmosDB

MongoDB, Aerospike, and Protobuf 2

Defining XDM field types in the API

The Schema Registry API allows you to define custom fields through the use of formats and optional constraints. See the guide on defining custom fields in the Schema Registry API for more information.