In ArangoDB how to select a node in graph filter by multi edge?

Question

Data like this

a->b,c,d
b->c,d
d->a,b

Query like this

FOR n in Nodes
FOR v,e,p IN 1 ANY n GRAPH 'MyGraph'
// Only need a
// HOW TO WRITE: FILTER n have an edge to `b` and n have an edge to `d`

// This will select a,b,c
FILTER v._key in [ 'b', 'd' ]
RETURN p

I want to select a node with edge to b and d, not b or d, but how ?

EDIT

Data

insert {_key:'a'} in nodes
insert {_key:'b'} in nodes
insert {_key:'c'} in nodes
insert {_key:'d'} in nodes

insert {_from:'nodes/a',_to:'nodes/b'} into relate
insert {_from:'nodes/a',_to:'nodes/c'} into relate
insert {_from:'nodes/a',_to:'nodes/d'} into relate
insert {_from:'nodes/b',_to:'nodes/c'} into relate
insert {_from:'nodes/b',_to:'nodes/d'} into relate
insert {_from:'nodes/c',_to:'nodes/d'} into relate

A very dummy solution is

for n in nodes
for v,e,p in 1 OUTBOUND n graph 'MyGraph'
filter v._key == 'b'
for v2,e2,p2 in 1 INBOUND v graph 'MyGraph'
sort v2._key == 'd'
return v2

But this query only work for two conditions,if I need one more condition I have to write one more for query.

score 1 · Accepted Answer · answered Mar 15 '17 at 12:28

I see several queries you could use. I added an vertex e to show how they look when you have more conditions.

I. the most performant query should be:

FOR v IN 1 INBOUND 'nodes/b' graph 'MyGraph'
  FILTER length(FOR d IN 1 OUTBOUND v graph 'MyGraph'
    FILTER d._key == 'd'
    LIMIT 1
    RETURN 1) == 1
  FILTER length(FOR e IN 1 OUTBOUND v graph 'MyGraph'
    FILTER e._key == 'e'
    LIMIT 1
    RETURN 1) == 1
  RETURN v

The query searchs for neighbors of b and filters over a sub-query with the founded neighbors and checks whether they are connected with d and e.

II. a more transparent but also slower query:

LET b = (FOR v IN 1 INBOUND "nodes/b" graph 'MyGraph' RETURN v)
LET d = (FOR v IN 1 INBOUND "nodes/d" graph 'MyGraph' RETURN v)
LET e = (FOR v IN 1 INBOUND "nodes/e" graph 'MyGraph' RETURN v)
RETURN INTERSECTION(b, d, e)

The query makes a sub-query for every searched node and returns the intersection of their neighbors.

III. a very generic query with use of bindVars, but also the slowest:

bind parameters:

{
    "targets": ["b","d","e"]
}

query:

FOR n IN nodes
  LET neighbors = (FOR v,e,p IN 1 OUTBOUND n graph 'MyGraph'
    FILTER v._key IN @targets
    RETURN v._key)
FILTER @targets ALL IN neighbors
RETURN n

Yes, it is the slowest but you have never to change the query itself any more when you want to add more conditions. You only have to change the bind parameters.

In ArangoDB how to select a node in graph filter by multi edge?

1 Answers1