Schema relationships

In a schema message, the Relationships array shows how different types can be connected, explaining the ways schema objects might relate to each other. These relationships show the overall structure of the data model and do not point to links between particular entities, events, or streaming data examples.

A schema relationship establish allowed relationship patterns between types, which are later used by instance messages to create relationships between individual objects at runtime.

All relationships in a schema message are type-to-type relationships that describe which kind of objects can be linked and how they are connected. For example:

• Defining logical associations between entity types, like an Asset related to a Location.

• Describing how streaming data types are associated with entities or events. For example, a Measurement stream describing an Equipment entity.

• Defining relationship patterns that may be reused.

Every schema relationship specifies a source and a target, both of which point to a schema object like a type or container. The destination system is responsible for enforcing the schema relationship.

Type-to-type relationship example

The following example shows a schema-level connection where a streaming data type represents an entity type.

{

"relationships": [

{

"source": {

"collection": "types", // types

"id": "typeid",

"property": "Pressure"

},

"target": {

"collection": "types", // types

"id": "containerTypeId"

},

"metadata": {

"id": "value"

}

}

]

}