Components - Family of functions¶

pgr_connectedComponents - Connected components of an undirected graph.
pgr_strongComponents - Strongly connected components of a directed graph.
pgr_biconnectedComponents - Biconnected components of an undirected graph.
pgr_articulationPoints - Articulation points of an undirected graph.
pgr_bridges - Bridges of an undirected graph.

Previous versions of this page

Supported versions: current(3.0) 2.6
Unsupported versions: 2.5

Parameters¶

Parameter	Type	Default	Description
Edges SQL	`TEXT`		Inner query as described below.

Inner query¶

Edges SQL:	an SQL query which should return a set of rows with the following columns:

Column	Type	Default	Description
id	`ANY-INTEGER`		Identifier of the edge.
source	`ANY-INTEGER`		Identifier of the first end point vertex of the edge.
target	`ANY-INTEGER`		Identifier of the second end point vertex of the edge.
cost	`ANY-NUMERICAL`		Weight of the edge (source, target) When negative: edge (source, target) does not exist, therefore it’s not part of the graph.
reverse_cost	`ANY-NUMERICAL`	-1	Weight of the edge (target, source), When negative: edge (target, source) does not exist, therefore it’s not part of the graph.

Where:

ANY-INTEGER:	SMALLINT, INTEGER, BIGINT
ANY-NUMERICAL:	SMALLINT, INTEGER, BIGINT, REAL, FLOAT

Result Columns¶

pgr_connectedComponents & pgr_strongComponents¶

Returns set of (seq, component, node)

Column	Type	Description
seq	`BIGINT`	Sequential value starting from 1.
component	`BIGINT`	Component identifier. It is equal to the minimum node identifier in the component.
node	`BIGINT`	Identifier of the vertex that belongs to component.

pgr_biconnectedComponents¶

Returns set of (seq, component, edge)

Column	Type	Description
seq	`BIGINT`	Sequential value starting from 1.
component	`BIGINT`	Component identifier. It is equal to the minimum edge identifier in the component.
edge	`BIGINT`	Identifier of the edge.

pgr_articulationPoints¶

Returns set of (node)

Column	Type	Description
node	`BIGINT`	Identifier of the vertex.

pgr_bridges¶

Returns set of (edge)

Column	Type	Description
edge	`BIGINT`	Identifier of the edge that is a bridge.

See Also¶

Indices and tables