Upstream and downstream

Transitive traversal: follow feeds relationships to any depth in a single query.

How it works

The upstream and downstream fields follow feeds relationships transitively, from a starting entity through the full chain of equipment, regardless of depth.

# Upstream: Zone ← VAV ← AHU ← Heat_Exchanger
zone(name: "Library") {
  fedBy { name type }
}

# Downstream: AHU → VAV → Zone
equipment(id: "TE01-XX-AHU-001") {
  downstream {
    name
    type
  }
}

Arguments

Argument	Type	Default	Description
maxDepth	Int	unlimited	Maximum number of hops to traverse
medium	String	all	Filter by distribution medium (AIR, CHILLED_WATER, HOT_WATER, CONDENSER_WATER)
is	String	all	Filter results to a specific Brick class (resolves subtypes)

Return type

Both upstream and downstream return [Equipment!]!, a flat list of equipment entities in traversal order (nearest first).

Examples

Basic upstream

{
  zone(name: "Library") {
    upstream {
      name
      type
    }
  }
}

With sensor data

{
  zone(name: "Library") {
    upstream {
      name
      type
      points(is: "Temperature_Sensor") {
        type
        currentValue { value timestamp }
      }
    }
  }
}

Filtered by medium

{
  equipment(id: "TE01-XX-AHU-001") {
    upstream(medium: "HOT_WATER") {
      name
      type
    }
  }
}

Filtered by type

{
  equipment(id: "TE01-XX-AHU-001") {
    downstream(is: "HVAC_Zone") {
      name
      type
    }
  }
}

Depth-limited

{
  zone(name: "Library") {
    upstream(maxDepth: 1) {
      name
      type
    }
  }
}

Equivalent SPARQL

The upstream field replaces this SPARQL pattern:

?zone ^brick:feeds+ ?equipment .

The downstream field replaces:

?equipment brick:feeds+ ?target .

Same traversal, expressed as declarative fields.