pgr_dijkstra - Deprecated Signature¶
Warning
This function signature is deprecated!!!
- That means it has been replaced by new signature(s)
- This signature is no longer supported, and may be removed from future versions.
- All code that use this function signature should be converted to use its replacement pgr_dijkstra (One to One).
Name¶
pgr_dijkstra — Returns the shortest path using Dijkstra algorithm.
Synopsis¶
Dijkstra’s algorithm, conceived by Dutch computer scientist Edsger Dijkstra in 1956. It is a graph search algorithm that solves the single-source shortest path problem for a graph with non-negative edge path costs, producing a shortest path tree. Returns a set of pgr_costResult (seq, id1, id2, cost) rows, that make up a path.
pgr_costResult[] pgr_dijkstra(text sql, integer source, integer target,
boolean directed, boolean has_rcost);
Description¶
sql: | a SQL query, which should return a set of rows with the following columns: SELECT id, source, target, cost [,reverse_cost] FROM edge_table
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source: | int4 id of the start point |
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target: | int4 id of the end point |
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directed: | true if the graph is directed |
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has_rcost: | if true, the reverse_cost column of the SQL generated set of rows will be used for the cost of the traversal of the edge in the opposite direction. |
Returns set of pgr_costResult[]:
seq: | row sequence |
---|---|
id1: | node ID |
id2: | edge ID (-1 for the last row) |
cost: | cost to traverse from id1 using id2 |
History
- Renamed in version 2.0.0
Examples: Directed¶
- Without reverse_cost
SELECT * FROM pgr_dijkstra(
'SELECT id::INTEGER, source::INTEGER, target::INTEGER, cost, reverse_cost FROM edge_table',
2,3, true, false);
NOTICE: Deprecated function
seq | id1 | id2 | cost
-----+-----+-----+------
(0 rows)
- With reverse_cost
SELECT * FROM pgr_dijkstra(
'SELECT id::INTEGER, source::INTEGER, target::INTEGER, cost, reverse_cost FROM edge_table',
2,3, true, true);
NOTICE: Deprecated function
seq | id1 | id2 | cost
-----+-----+-----+------
0 | 2 | 4 | 1
1 | 5 | 8 | 1
2 | 6 | 9 | 1
3 | 9 | 16 | 1
4 | 4 | 3 | 1
5 | 3 | -1 | 0
(6 rows)
Examples: Undirected¶
- Without reverse_cost
SELECT * FROM pgr_dijkstra(
'SELECT id::INTEGER, source::INTEGER, target::INTEGER, cost FROM edge_table',
2, 3, false, false);
NOTICE: Deprecated function
seq | id1 | id2 | cost
-----+-----+-----+------
0 | 2 | 4 | 1
1 | 5 | 8 | 1
2 | 6 | 5 | 1
3 | 3 | -1 | 0
(4 rows)
- With reverse_cost
SELECT * FROM pgr_dijkstra(
'SELECT id::INTEGER, source::INTEGER, target::INTEGER, cost, reverse_cost FROM edge_table',
2, 3, false, true);
NOTICE: Deprecated function
seq | id1 | id2 | cost
-----+-----+-----+------
0 | 2 | 2 | 1
1 | 3 | -1 | 0
(2 rows)
The queries use the Sample Data network.