pgr_bridges - Experimental¶
pgr_bridges
- Return the bridges of an undirected graph.
Warning
Experimental functions
- They are not officially of the current release.
- They likely will not be officially be part of the next release:
- The functions might not make use of ANY-INTEGER and ANY-NUMERICAL
- Name might change.
- Signature might change.
- Functionality might change.
- pgTap tests might be missing.
- Might need c/c++ coding.
- May lack documentation.
- Documentation if any might need to be rewritten.
- Documentation examples might need to be automatically generated.
- Might need a lot of feedback from the comunity.
- Might depend on a proposed function of pgRouting
- Might depend on a deprecated function of pgRouting
Synopsis¶
A bridge is an edge of an undirected graph whose deletion increases its number of connected components. This implementation can only be used with an undirected graph.
Characteristics¶
The main Characteristics are:
- The returned values are ordered:
- edge ascending
- Running time: \(O(E * (V + E))\)
Signatures¶
pgr_bridges(edges_sql)
RETURNS SET OF (seq, node)
OR EMPTY SET
The signature is for a undirected graph.
Example: |
---|
SELECT * FROM pgr_bridges(
'SELECT id, source, target, cost, reverse_cost FROM edge_table'
);
seq | edge
-----+------
1 | 1
2 | 6
3 | 7
4 | 14
5 | 17
6 | 18
(6 rows)

Description of the Signatures¶
Description of the edges_sql query for components functions¶
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)
|
|
reverse_cost | ANY-NUMERICAL |
-1 | Weight of the edge (target, source),
|
Where:
ANY-INTEGER: | SMALLINT, INTEGER, BIGINT |
---|---|
ANY-NUMERICAL: | SMALLINT, INTEGER, BIGINT, REAL, FLOAT |
Description of the parameters of the signatures¶
Parameter | Type | Default | Description |
---|---|---|---|
edges_sql | TEXT |
SQL query as described above. |
Description of the return values for bridges¶
Returns set of (seq, node)
Column | Type | Description |
---|---|---|
seq | INT |
Sequential value starting from 1. |
edge | BIGINT |
Identifier of the edge. |
See Also¶
- http://en.wikipedia.org/wiki/Bridge_%28graph_theory%29
- The queries use the Sample Data network.
Indices and tables