Learning > presentation > Relationship Path Specification

RelationshipPath Specification

Based on RepeatableRelationshipPathSpecification interface.

Relationship path specification and it's repeatable counterpart are used to define paths from one ECClass to another, optionally traversing through multiple relationships.

Attributes

Name	Required?	Type	Default	Meaning
`relationship`	Yes	`SingleSchemaClassSpecification`		Specification of the relationship to follow.
`direction`	Yes	`"Forward" \| "Backward"`		Direction in which the relationship should be followed.
`targetClass`	No	`SingleSchemaClassSpecification`	Other end of relationship	Specification of the related class.
`count`	No	`number \| "*"`	1	Number of times the relationship should be traversed. `"*"` makes the step optional, so results of previous step are also included in results of this step, no matter if this step has any output of its own or not.

Example

A single-step relationship path which simply jumps from current ECClass to BisCore.PhysicalElement through BisCore.ModelModelsElement relationship:

{
  "relationship": { "schemaName": "BisCore", "className": "ModelModelsElement" },
  "direction": "Forward",
  "targetClass": { "schemaName": "BisCore", "className": "PhysicalElement" }
}

A multi-step relationship path which jumps from current ECClass through BisCore.ElementOwnsChildElements relationship two times in a backward direction:

{
  "relationship": { "schemaName": "BisCore", "className": "ElementOwnsChildElements" },
  "direction": "Backward",
  "count": 2
}

A two-step relationship path that first jumps from current ECClass through BisCore.ModelModelsElement and then through BisCore.ElementOwnsUniqueAspects:

[{
  "relationship": { "schemaName": "BisCore", "className": "ModelModelsElement" },
  "direction": "Forward"
}, {
  "relationship": { "schemaName": "BisCore", "className": "ElementOwnsUniqueAspects" },
  "direction": "Forward"
}]

A recursive relationship path which recursively walks through a relationship and accumulates all ECInstances it finds:

{
  "relationship": { "schemaName": "BisCore", "className": "ElementOwnsChildElements" },
  "direction": "Forward",
  "count": "*"
}

A two-step relationship path that first jumps from current ECClass through BisCore.ModelModelsElement, then recursively walks through BisCore.ElementOwnsChildElements relationship and then finds all related BisCore.ElementUniqueAspects:

[{
  "relationship": { "schemaName": "BisCore", "className": "ModelModelsElement" },
  "direction": "Forward"
}, {
  "relationship": { "schemaName": "BisCore", "className": "ElementOwnsChildElements" },
  "direction": "Forward",
  "count": "*"
}, {
  "relationship": { "schemaName": "BisCore", "className": "ElementOwnsUniqueAspects" },
  "direction": "Forward",
  "targetClass": { "schemaName": "BisCore", "className": "ElementUniqueAspect" }
}]

A two-step relationship path that finds all BisCore.Elements related to current ECClass through BisCore.ModelModelsElement, then finds all recursively related BisCore.Elements to BisCore.Elements from the first step through BisCore.ElementOwnsChildElements relationship:

[{
  "relationship": { "schemaName": "BisCore", "className": "ModelModelsElement" },
  "direction": "Forward"
}, {
  "relationship": { "schemaName": "BisCore", "className": "ElementOwnsChildElements" },
  "direction": "Forward",
  "count": "*"
}]

A three-step relationship path that finds all BisCore.GeometricElement3d related to current ECClass through BisCore.ModelContainsElements relationship, then finds all BisCore.SpatialCategorys related to BisCore.GeometricElement3ds found in the previous step through BisCore.GeometricElement3dIsInCategory relationship and finds all BisCore.SubCategorys related to BisCore.SpatialCategorys found in the previous step through BisCore.CategoryOwnsSubCategories relationship. Result includes BisCore.GeometricElement3ds, BisCore.SpatialCategorys and BisCore.SubCategorys:

[{
  "relationship": { "schemaName": "BisCore", "className": "ModelContainsElements" },
  "direction": "Forward",
  "targetClass": { "schemaName": "BisCore", "className": "GeometricElement3d" },
  "count": "*"
}, {
  "relationship": { "schemaName": "BisCore", "className": "GeometricElement3dIsInCategory" },
  "direction": "Forward",
  "targetClass": { "schemaName": "BisCore", "className": "SpatialCategory" },
  "count": "*"
}, {
  "relationship": { "schemaName": "BisCore", "className": "CategoryOwnsSubCategories" },
  "direction": "Forward",
  "count": "*"
}]

Last Updated: 29 November, 2022