Model: Relation Instance

A relation instance is a connection between an outbound entity instance and an inbound entity instance. The relation instance has a type, the relation type. The relation type defines which entity type the outbound entity type and which entity type the inbound entity type must have.

Instance Id / Cardinality

The relation instance is a unique link for the following combination:

• Outbound Entity Instance
• Inbound Entity Instance
• Relation Type
• Instance Id

There are multiple types of instance ids:

1. Only one instance of the same relation type is allowed between the outbound entity instance and the inbound entity instance (Cardinality: 0..1). In this case the instance id is an empty string.
2. The relation instance depends on properties. For example, only one connector can exist between an output property of the outbound entity instance and an input property of the inbound entity instance. In this case the instance id is a string calculated by the property names of the output property and the input property. This will prevent that multiple connectors of the same type exist between the same properties.
3. There is no restriction for a relation instance between the outbound entity instance and the inbound entity instance (Cardinality: 0..N). In this case a random string will be generated as instance id. This allows to create multiple relation instances of the same type between the same outbound entity instance and inbound entity instance.

Data Model

Graph

graph LR;
    A(Outbound Entity Instance)===>|"Relation Instance"|B(Inbound Entity Instance);

ER Diagram

erDiagram
    Entity-Type {
        string namespace
        string name
    }
    Entity-Instance {
        string id
        string label
    }
    Relation-Type {
        string namespace
        string name
    }
    Relation-Instance {
        string instanceId
    }
    Property-Type {
        string name
        enum DataType
        enum SocketType
        enum Mutability
    }
    Property-Instance {
        string name
        JSON value
    }
    Entity-Instance ||--}o Property-Instance : stores
    Entity-Instance o{--}o Relation-Instance : outbound
    Entity-Instance o{--}o Relation-Instance : inbound
    Relation-Instance ||--}o Property-Instance : stores
    Relation-Instance o{--|| Relation-Type : is-a
    Property-Instance o{--|| Property-Type : is-a
    Entity-Instance o{--|| Entity-Type : is-a
    Relation-Type ||--}o Property-Type : defines
    Entity-Type ||--}o Relation-Type : outbound
    Entity-Type ||--}o Relation-Type : inbound
    Entity-Type ||--}o Property-Type : defines

GraphQL

JSON Schema