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/* :file: This file is part of the pgRouting project.
:copyright: Copyright (c) 2016-2026 pgRouting developers
:license: Creative Commons Attribution-Share Alike 3.0 https://creativecommons.org/licenses/by-sa/3.0 */
DROP TABLE IF EXISTS linegraph_edges;
DROP TABLE IF EXISTS vertex_map;
DROP TABLE IF EXISTS new_graph;
/* -- q0 */
SELECT id, source, target, cost, reverse_cost
FROM edges
WHERE id IN (4, 7, 8, 10);
/* -- q1 */
SELECT * FROM pgr_lineGraphFull(
$$SELECT id, source, target, cost, reverse_cost
FROM edges
WHERE id IN (4, 7, 8, 10)$$);
/* -- q2 */
SELECT seq AS id, source, target, cost, edge
INTO lineGraph_edges
FROM pgr_lineGraphFull(
$$SELECT id, source, target, cost, reverse_cost
FROM edges
WHERE id IN (4, 7, 8, 10)$$);
/* -- q3 */
SELECT id, NULL::BIGINT original_id
INTO vertex_map
FROM vertices;
/* -- q4 */
INSERT INTO vertex_map (id)
(SELECT id
FROM pgr_extractVertices(
$$SELECT id, source, target FROM lineGraph_edges$$) WHERE id < 0);
/* -- q5 */
UPDATE vertex_map
SET original_id = id
WHERE id > 0;
/* -- q6 */
SELECT *
FROM vertex_map ORDER BY id DESC;
/* -- q7 */
SELECT *, source AS targets_original_id
FROM lineGraph_edges
WHERE cost = 0 and source > 0;
/* -- q8 */
WITH
self_loops AS (
SELECT DISTINCT source, target, source AS targets_original_id
FROM lineGraph_edges
WHERE cost = 0 and source > 0)
UPDATE vertex_map SET original_id = targets_original_id
FROM self_loops WHERE target = id;
/* -- q9 */
SELECT *
FROM vertex_map WHERE id < 0
ORDER BY id DESC;
/* -- q10 */
WITH
assigned_vertices
AS (SELECT id, original_id
FROM vertex_map
WHERE original_id IS NOT NULL),
cross_edges
AS (SELECT DISTINCT e.source, v.original_id AS source_original_id
FROM lineGraph_edges AS e
JOIN vertex_map AS v ON (e.target = v.id)
WHERE source NOT IN (SELECT id FROM assigned_vertices)
)
UPDATE vertex_map SET original_id = source_original_id
FROM cross_edges WHERE source = id;
/* -- q11 */
SELECT *
FROM vertex_map WHERE id < 0
ORDER BY id DESC;
/* -- q12 */
SELECT seq, path_seq, start_vid, end_vid, node, original_id, edge, cost, agg_cost
FROM (SELECT * FROM pgr_dijkstraNear(
$$SELECT * FROM lineGraph_edges$$,
(SELECT array_agg(id) FROM vertex_map where original_id = 6),
(SELECT array_agg(id) FROM vertex_map where original_id = 3))) dn
JOIN vertex_map AS v1 ON (node = v1.id);
/* -- q13 */
SELECT edge FROM pgr_dijkstraNear(
$$SELECT * FROM lineGraph_edges$$,
(SELECT array_agg(id) FROM vertex_map where original_id = 6),
(SELECT array_agg(id) FROM vertex_map where original_id = 3))
WHERE cost = 0 AND seq != 1 AND edge != -1;
/* -- q14 */
UPDATE lineGraph_edges
SET cost = 100
WHERE id IN (
SELECT edge FROM pgr_dijkstraNear(
$$SELECT * FROM lineGraph_edges$$,
(SELECT array_agg(id) FROM vertex_map where original_id = 6),
(SELECT array_agg(id) FROM vertex_map where original_id = 3))
WHERE cost = 0 AND seq != 1 AND edge != -1);
/* -- q15 */
WITH
results AS (
SELECT * FROM pgr_dijkstraNear(
$$SELECT * FROM lineGraph_edges$$,
(SELECT array_agg(id) FROM vertex_map where original_id = 6),
(SELECT array_agg(id) FROM vertex_map where original_id = 3)))
SELECT seq, path_seq, start_vid, end_vid, node, original_id, edge, cost, agg_cost
FROM results
LEFT JOIN vertex_map AS v1 ON (node = v1.id) ORDER BY seq;
/* -- q16 */
WITH
u_turns AS (
SELECT e.id AS eid, v1.original_id
FROM linegraph_edges as e
JOIN vertex_map AS v1 ON (source = v1.id)
AND v1.original_id IN (3, 6, 8, 11))
UPDATE lineGraph_edges
SET source = original_id
FROM u_turns
WHERE id = eid;
/* -- q17 */
WITH
u_turns AS (
SELECT e.id AS eid, v1.original_id
FROM linegraph_edges as e
JOIN vertex_map AS v1 ON (target = v1.id)
AND v1.original_id IN (3, 6, 8, 11))
UPDATE lineGraph_edges
SET target = original_id
FROM u_turns
WHERE id = eid;
/* -- q18 */
SELECT * FROM linegraph_edges
WHERE source = target
ORDER BY id;
/* -- q19 */
DELETE FROM linegraph_edges
WHERE source = target;
/* -- q20 */
WITH
results AS (
SELECT * FROM pgr_dijkstra(
$$SELECT * FROM lineGraph_edges$$, 6, 3))
SELECT seq, path_seq, node, original_id, edge, cost, agg_cost
FROM results
LEFT JOIN vertex_map AS v1 ON (node = v1.id) ORDER BY seq;
/* -- q21 */
SELECT id, source, target, cost, reverse_cost
INTO new_graph from edges
WHERE id NOT IN (4, 7, 8, 10);
/* -- q22 */
CREATE SEQUENCE new_graph_id_seq;
ALTER TABLE new_graph ALTER COLUMN id SET DEFAULT nextval('new_graph_id_seq');
ALTER TABLE new_graph ALTER COLUMN id SET NOT NULL;
ALTER SEQUENCE new_graph_id_seq OWNED BY new_graph.id;
SELECT setval('new_graph_id_seq', (SELECT max(id) FROM new_graph));
/* -- q23 */
INSERT INTO new_graph (source, target, cost, reverse_cost)
SELECT source, target, cost, -1 FROM lineGraph_edges;
/* -- q24 */
WITH
results AS (
SELECT * FROM pgr_dijkstra(
$$SELECT * FROM new_graph$$, 6, 3))
SELECT seq, path_seq, node, original_id, edge, cost, agg_cost
FROM results
LEFT JOIN vertex_map AS v1 ON (node = v1.id) ORDER BY seq;
/* -- q25 */
WITH
results AS (
SELECT * FROM pgr_dijkstra(
$$SELECT * FROM new_graph$$, 5, 1))
SELECT seq, path_seq, node, original_id, edge, cost, agg_cost
FROM results
LEFT JOIN vertex_map AS v1 ON (node = v1.id) ORDER BY seq;
/* -- q26 */
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