How can we create undirected edge between two nodes in apache age graph database - graph-databases

Question

How do I connect undirected edge between these 2 nodes as follow :
SELECT * from cypher(
'munmud_graph',
$$
CREATE (v:Country {"name" : "Bangladesh"})
RETURN v
$$
) as (v agtype);
SELECT * from cypher(
'munmud_graph',
$$
CREATE (v:Country {"name" : "India"})
RETURN v
$$
) as (v agtype);
I want to connect these two node with an undirected edge with label Neighbour

Answer 1

Creating and storing of undirected edges are is supported, although you can read/query-for edges and ignore their direction.
To create the edge, you would do something like the following:
SELECT * from cypher(
'munmud_graph',
$$
MATCH
(x:Country),
(y:Country)
WHERE x.name = 'Bangladesh' AND y.name = 'India'
CREATE (x)-[r:Neighbour]->(y)
RETURN r
$$
) as (r agtype);
And then to query for the edge and ignore its direction, you would do:
SELECT * from cypher(
'munmud_graph',
$$
MATCH (x:Country)-[r]-(y:Country)
WHERE x.name = 'Bangladesh' AND y.name = 'India'
RETURN r
$$
) as (r agtype);

Answer 2

I believe that, as of today, the only way to do this with Apache AGE is to set the edge with a property that resembles this undirection or set it as bidirectional.
Considering that, both of the following examples doesn't work:
-- EXAMPLE 1 : UNDIRECTED EDGE (DOES NOT WORK)
SELECT * FROM cypher ('demo', $$
MATCH (a:Country), (b:Country)
WHERE a.name = "India" AND b.name = "Bangladesh"
CREATE (a)-[e:BORDERS_WITH]-(b)
RETURN e
$$) as (e agtype);
ERROR: only directed relationships are allowed in CREATE
LINE 4: CREATE (a)-[e:BORDERS_WITH]-(b)
-- EXAMPLE 2 : BIDIRECTIONAL EDGE (DOES NOT WORK)
SELECT * FROM cypher ('demo', $$
MATCH (a:Country), (b:Country)
WHERE a.name = "India" AND b.name = "Bangladesh"
CREATE (a)<-[e:BORDERS_WITH]->(b)
RETURN e
$$) as (e agtype);
ERROR: syntax error at or near ">"
LINE 4: CREATE (a)<-[e:BORDERS_WITH]->(b)
But this works:
-- EXAMPLE 3 : SET BIDIRECTIONAL EDGE AS PROPERTY (WORKS)
SELECT * FROM cypher ('demo', $$
MATCH (a:Country), (b:Country)
WHERE a.name = "India" AND b.name = "Bangladesh"
CREATE (a)-[e:BORDERS_WITH{ type:"<->" }]->(b)
RETURN e
$$) as (e agtype);
e
--------------------------------------------------------------------------------------------------------------------------------------------------
{"id": 2533274790395905, "label": "BORDERS_WITH", "end_id": 2251799813685249, "start_id": 2251799813685250, "properties": {"type": "<->"}}::edge
(1 row)
demo=#
Then, if you want to find which edges are of type "<->" you just have to type this query:
SELECT * FROM cypher ('demo', $$
MATCH (a)-[e:BORDERS_WITH]->(b)
WHERE e.type = "<->"
RETURN e
$$) as (e agtype);
e
--------------------------------------------------------------------------------------------------------------------------------------------------
{"id": 2533274790395905, "label": "BORDERS_WITH", "end_id": 2251799813685249, "start_id": 2251799813685250, "properties": {"type": "<->"}}::edge
(1 row)

Answer 3

What you can do is create a directed Relationship between the nodes and you would have an edge both ways, e.g :
I run the command:
And now when you Display the edges it would show you both countries:

Answer 4

SELECT * from cypher(
'munmud_graph',
$$
MATCH (a:Country {name: "Bangladesh"}), (b:Country {name: "India"})
CREATE (a)-[:Neighbour]->(b)
RETURN a, b
$$
) as (a, b);
Hope this will work for you