Page Comparison

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The following demonstrates in more detail the example where properties from an existing "country" domain  domain is to be referenced by a new domain called "students".  Assume the "country" domain  domain contains many properties including the country " name " and the address for the immigration office. The "students" domain student domain will reference the "countries" domain twice 1)  domain twice:

1. In a property called

...

1. homeCountry 
2. A property called immigrationAddress

GET the

...

address

...

 Property in the

...

countries

...

 Model Schema

GET /domains/country/properties?version=1

...

[
	{
			.
			.
		"propertyName": "immigrationAddress",
		"propertyType": "node",
				.
			.
	},
	{
			.
			.
		"propertyName": "name",
		"propertyType": "string"
			.
			.
	}
]

Add the Cross-Reference into the

...

students

...

 Model Schema and POST a New Domain

POST /domains

{
	"name": "students",
	"modelSchema": {
		"properties": {
			"homeCountry": {
				"type": "uri",
				"uriType": "xref",
				"xrefLocation": "/mdr/country:v1/name"
			},
			"immigrationAddress": {
				"type": "uri",
				"uriType": "xref",
				"xrefLocation": "/mdr/country:v1/immigrationAddress"
			},
			    .
		        .
                .
		}
	}
}

Note that `homeCountry` is homeCountry is a primitive type while `immigrationAddress` is immigrationAddress is a node and  contains several items such as street, city, province-state, postal-code.

Again, the "stuents" domain students domain could just reference the "country" MDR  MDR once which would cause the entire "country" MDR  MDR to be inserted.

How to Establish Circular Cross-References

Consider the situation where a "state" domain  domain needs to reference to "country" and "country" needs  and country needs a reference back to multiple "state" MDRs MDRs.

This creates a problem since the schema for one will exist before the other. To remedy one of the domains can be updated after both are created. For example:

1. POST the domain for "state" state with a modelSchema model schema that includes a reference to "country" with  with no `xrefLocation` xrefLocation:

"name": {
	"type": "string"
},
"country": {
	"type": "uri",
	"uriType": "xref"
}	

2. POST the domain for "country" with  with a modelSchema model schema that includes a reference to "state" including  including the `xrefLocation` xrefLocation:

"name": {
	"type": "string"
},
"state": {
	"type": "uri",
	"uriType":"xref"
}

3. PUT the domain for "state" with  with a modelSchema model schema that includes the reference to "country":

"name": {
	"type": "string"
},
"country": {
	"type": "uri",
	"uriType": "xref",
	"xrefLocation": "/domain/country:v1/name"
}

Data can be posted only if all uri's of type `xref` have valid `xrefLocation`s xref have valid xrefLocation`s.

NOTE: PUTing a domain is denied if any data is POSTed to the domain:version.

Using UUIDs

The underlying store in YOUnite uses UUIDs to access data elements.  UUIDs can be used instead of domain paths. See Using UUIDs Instead of Domain or MDR Pathnames for more.