Relationship

Relationship is defined in KerML specification on page 143. Excerpt from the machine readable specification:

A Relationship is an Element that relates other Element. Some of its relatedElements may be owned, in which case those ownedRelatedElements will be deleted from a model if their owningRelationship is. A Relationship may also be owned by another Element, in which case the ownedRelatedElements of the Relationship are also considered to be transitively owned by the owningRelatedElement of the Relationship.

The relatedElements of a Relationship are divided into source and target Elements. The Relationship is considered to be directed from the source to the target Elements. An undirected Relationship may have either all source or all target Elements.

A “relationship Element” in the abstract syntax is generically any Element that is an instance of either Relationship or a direct or indirect specialization of Relationship. Any other kind of Element is a “non-relationship Element”. It is a convention of that non-relationship Elements are only related via reified relationship Elements. Any meta-associations directly between non-relationship Elements must be derived from underlying reified Relationship.

The following diagram shows the inheritance hierarchy of Relationship according to the specification:

// Class: Relationship
digraph {
Relationship [label="Relationship (KerML)" shape=plaintext]
Element -> Relationship
Element [label="Element (KerML)" shape=plaintext]
}

The following table shows all attributes defined for Relationship according to the specification together with the documentation from the machine readable specification. Note that in SysIDE API, we use snake case for attribute names instead of Pascal case used in the specification.

Attribute	Documentation from machine readable specification
Attributes defined in `Relationship`:
`is_implied`	Whether this Relationship was generated by tooling to meet semantic rules, rather than being directly created by a modeler.
`owned_related_elements`	The relatedElements of this Relationship that are owned by the Relationship.
`owning_related_element`	The relatedElement of this Relationship that owns the Relationship, if any.
`related_elements`	The Elements that are related by this Relationship, derived as the union of the `source` and `target` Elements of the Relationship.
`sources`	The `relatedElements from which this Relationship is considered to be directed.`
`targets`	The `relatedElements` to which this Relationship is considered to be directed.
Attributes defined in `Element`:
`declared_name`	The declared name of this `Element`.
`declared_short_name`	An optional alternative name for the `Element` that is intended to be shorter or in some way more succinct than its primary `name`. It may act as a modeler-specified identifier for the `Element`, though it is then the responsibility of the modeler to maintain the uniqueness of this identifier within a model or relative to some other context.
`documentation`	The Documentation owned by this Element.
`element_id`	The globally unique identifier for this Element. This is intended to be set by tooling, and it must not change during the lifetime of the Element.
`is_implied_included`	Whether all necessary implied Relationships have been included in the `ownedRelationships` of this Element. This property may be true, even if there are not actually any `ownedRelationships` with `isImplied = true`, meaning that no such Relationships are actually implied for this Element. However, if it is false, then `ownedRelationships` may not contain any implied Relationships. That is, either all required implied Relationships must be included, or none of them.
`is_library_element`	Whether this Element is contained in the ownership tree of a library model.
`name`	The name to be used for this `Element` during name resolution within its `owningNamespace`. This is derived using the `effectiveName()` operation. By default, it is the same as the `declaredName`, but this is overridden for certain kinds of `Elements` to compute a `name` even when the `declaredName` is null.
`owned_annotations`	The `ownedRelationships` of this `Element` that are `Annotations`, for which this `Element` is the `annotatedElement`.
`owned_elements`	The Elements owned by this Element, derived as the ownedRelatedElements of the ownedRelationships of this Element.
`owned_relationships`	The Relationships for which this Element is the owningRelatedElement.
`owner`	The owner of this Element, derived as the `owningRelatedElement` of the `owningRelationship` of this Element, if any.
`owning_membership`	The `owningRelationship` of this `Element`, if that `Relationship` is a `Membership`.
`owning_namespace`	The `Namespace` that owns this `Element`, which is the `membershipOwningNamespace` of the `owningMembership` of this `Element`, if any.
`owning_relationship`	The Relationship for which this Element is an ownedRelatedElement, if any.
`qualified_name`	The full ownership-qualified name of this `Element`, represented in a form that is valid according to the KerML textual concrete syntax for qualified names (including use of unrestricted name notation and escaped characters, as necessary). The `qualifiedName` is null if this `Element` has no `owningNamespace` or if there is not a complete ownership chain of named `Namespaces` from a root `Namespace` to this `Element`.
`short_name`	The short name to be used for this `Element` during name resolution within its `owningNamespace`. This is derived using the `effectiveShortName()` operation. By default, it is the same as the `declaredShortName`, but this is overridden for certain kinds of `Elements` to compute a `shortName` even when the `declaredName` is null.
`textual_representations`	The `TextualRepresentations` that annotate this `Element`.