Represent xs:choice as JSON schema

Question

Wrapping my head around JSON Schema's oneOf.

I want to produce a JSON version of an XML format and have a JSON schema validate the essential aspects (I know there'll be some differences).

I have an XML Schema concept where you can specify a name or ID for some entity:

<xs:element name="Entity" type="test:EntityType" />
    <xs:complexType name="EntityType">
        <xs:choice>
            <xs:element name="EntityID" />
            <xs:element name="EntityName" />
        </xs:choice>
    </xs:complexType>

In the corresponding JSON schema I'm having trouble with where to put the oneOf object.

In the JSON schema examples it looks like you should put complete schemas into oneOf, is that right? How should this look in the general case? Has anyone documented the similarities and differences between XSD and JSON schema for reference?

Answer 1

I didn't try it myself, but I think you need something like this:

{
    "allOf" : [
        {
            "type" : "object",
            "properties" : {
                "entityName" : {"type" : "string"},
                "entityID" : {"type" : "integer"}
            }
        },
        {
            "oneOf" : [
                {
                    "required" : ["entityName"]
                },
                {
                    "required" : ["entityID"]
                }
            ]
        }
    ]
}

So after under a top-level "allOf" you first describe the basic structure, then with a "oneOf" you express the choice.