DocumentationExperience PlatformExperience Data Model (XDM) Guide

Schema Registry API guide appendix

Last update: Thu Aug 24 2023 00:00:00 GMT+0000 (Coordinated Universal Time)

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This document provides supplemental information related to working with the Schema Registry API.

Using query parameters query

The Schema Registry supports the use of query parameters to page and filter results when listing resources.

NOTE
When combining multiple query parameters, they must be separated by ampersands (&).

Paging paging

The most common query parameters for paging include:

Parameter
Description
orderby
Sort results by a specific property. Example: orderby=title will sort results by title in ascending order (A-Z). Adding a - before the parameter value (orderby=-title) will sort items by title in descending order (Z-A).
limit
When used in conjunction with an orderby parameter, limit restricts the maximum number of items that should be returned for a given request. This parameter cannot be used without an orderby parameter present.

The limit parameter specifies a positive integer (between 0 and 500) as a hint as to the maximum number of items that should be returned. For example, limit=5 returns only five resources in the list. However, this value is not strictly honored. The actual response size may be smaller or larger as constrained by the need to provide the reliable operation of the start parameter, if one is provided.
start
When used in conjunction with an orderby parameter, start specifies where the sub-setted list of items should begin. This parameter cannot be used without an orderby parameter present. This value can be obtained from the _page.next attribute of a list response, and used to access the next page of results. If the _page.next value is null, then there is no additional page available.

Typically, this parameter is omitted in order to obtain the first page of results. After that, start should be set to the maximum value of the primary sort property of the orderby field received in the previous page. The API response then returns entries beginning with those that have a primary sort property from orderby strictly greater than (for ascending) or strictly less than (for descending) the specified value.

For example, if the orderby parameter is set to orderby=name,firstname, the start parameter would contain a value for the name property. In this case, if you wanted to show the next 20 entries of a resource immediately following the name “Miller”, you would use: ?orderby=name,firstname&start=Miller&limit=20.

Filtering filtering

You can filter results by using the property parameter, which is used to apply a specific operator against a given JSON property within the retrieved resources. Supported operators include:

Operator
Description
Example
==
Filters by whether the property equals the provided value.
property=title==test
!=
Filters by whether the property does not equal the provided value.
property=title!=test
<
Filters by whether the property is less than the provided value.
property=version<5
>
Filters by whether the property is greater than the provided value.
property=version>5
<=
Filters by whether the property is less than or equal to the provided value.
property=version<=5
>=
Filters by whether the property is greater than or equal to the provided value.
property=version>=5
(None)
Stating only the property name returns only entries where the property exists.
property=title
TIP
You can use the property parameter to filter schema field groups by their compatible class. For example, property=meta:intendedToExtend==https://ns.adobe.com/xdm/context/profile returns only field groups that are compatible with the XDM Individual Profile class.

Compatibility Mode compatibility

Experience Data Model (XDM) is a publicly documented specification, driven by Adobe to improve the interoperability, expressiveness, and power of digital experiences. Adobe maintains the source code and formal XDM definitions in an open source project on GitHub. These definitions are written in XDM Standard Notation, using JSON-LD (JavaScript Object Notation for Linked Data) and JSON Schema as the grammar for defining XDM schemas.

When looking at formal XDM definitions in the public repository, you can see that standard XDM differs from what you see in Adobe Experience Platform. What you are seeing in Experience Platform is called Compatibility Mode, and it provides a simple mapping between standard XDM and the way it is used within Platform.

How Compatibility Mode works

Compatibility Mode allows the XDM JSON-LD model to work with existing data infrastructure by altering values within standard XDM while keeping the semantics the same. It uses a nested JSON structure, displaying schemas in a tree-like format.

The main difference you will notice between standard XDM and Compatibility Mode is the removal of the “xdm:” prefix for field names.

The following is a side-by-side comparison showing birthday-related fields (with “description” attributes removed) in both standard XDM and Compatibility Mode. Notice that the Compatibility Mode fields include a reference to the XDM field and its data type in the “meta:xdmField” and “meta:xdmType” attributes.

Standard XDM
Compatibility Mode
{
  "xdm:birthDate": {
    "title": "Birth Date",
    "type": "string",
    "format": "date"
  },
  "xdm:birthDayAndMonth": {
    "title": "Birth Date",
    "type": "string",
    "pattern": "[0-1][0-9]-[0-9][0-9]"
  },
  "xdm:birthYear": {
    "title": "Birth year",
    "type": "integer",
    "minimum": 1,
    "maximum": 32767
  }
}


{
  "birthDate": {
    "title": "Birth Date",
    "type": "string",
    "format": "date",
    "meta:xdmField": "xdm:birthDate",
    "meta:xdmType": "date"
  },
  "birthDayAndMonth": {
    "title": "Birth Date",
    "type": "string",
    "pattern": "[0-1][0-9]-[0-9][0-9]",
    "meta:xdmField": "xdm:birthDayAndMonth",
    "meta:xdmType": "string"
  },
  "birthYear": {
    "title": "Birth year",
    "type": "integer",
    "minimum": 1,
    "maximum": 32767,
    "meta:xdmField": "xdm:birthYear",
    "meta:xdmType": "short"
  }
}

Why is Compatibility Mode necessary?

Adobe Experience Platform is designed to work with multiple solutions and services, each with their own technical challenges and limitations (for example, how certain technologies handle special characters). In order to overcome these limitations, Compatibility Mode was developed.

Most Experience Platform services including Catalog, Data Lake, and Real-Time Customer Profile use Compatibility Mode in lieu of standard XDM. The Schema Registry API also uses Compatibility Mode, and the examples in this document are all shown using Compatibility Mode.

It is worthwhile to know that a mapping takes place between standard XDM and the way it is operationalized in Experience Platform, but it should not affect your use of Platform services.

The open source project is available to you, but when it comes to interacting with resources through the Schema Registry, the API examples in this document provide the best practices you should know and follow.

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