OrientDB从起始顶点获取所有连接的顶点

Question

I'm working with Neo4j and OrientDB and I will compare their performance and functionality regarding traversal (Java Traversal API in Neo4j and Native Fluent API in OrientDB).

For OrientDB it should be possible to start at a specific vertex and get all vertices which are reachable and also an intersection of the property access on each individual step exists. If you have for example the graph A --> B --> C --> D , where A, B and C has access = www and D has the values access = https , the vertices A, B and C should be returned.

I recently asked a question and afterwards I posted my solution, how comparison on properties is possible on Neo4j.

Neo4j node property comparison during traversal

In Neo4j it is possible to create a TraversalDescription, which describes the rules and the bahavior of the traversal. For example the following: the AccesListEvaluator will compare the property of two connected nodes, as you can see on the posted solution for above mentioned Neo4j comparison.

TraversalDescription td = db.traversalDescription().depthFirst()
            .relationships(RelationshipLabel.REFERENCED_BY, Direction.OUTGOING)
            .evaluator(new AccessListEvaluator());

If you execute the following code example, you will get back all reachable nodes from the startNode and you could iterate over them and extract all their properties.

td.traverse(startNode).nodes();

I need alle the nodes, because I have to extract their properties and store it in a own data structure.

Is a similar solution with the OrientDB Native Fluent API possible? I checked the manual Java Traverse , but I'm not able to deviate a working solution from the given examples. If I'm execute the following code example I just get the properties and the IN and OUT connections of the target.

for (OIdentifiable oi : new OTraverse().field("in").field("out").target(new ORecordId("#24:0"))) {
            System.out.println(oi);
}

For me it looks like, that you only get back the possible connections to other nodes. Is there any chance, with the Native API to get each vertex and the properties of each vertex?

Hopefully my question is understandable. Thanks in advance

Answer 1

I think I'm working on a similar problem. I'm using python (PyOrient) to connect to OrientDB and I'm generally using the SQL syntax. I've been trying to leverage either TRAVERSE or a fetchPlan.

When I use TRAVERSE I'm able to get all of the vertices and eges with properties with a query like this in console (same result in studio):

orientdb {db=FetchPlanTesting}> traverse * from level01

----+------+---------+------------------+------------+------+------+-------------
#   |@RID  |@CLASS   |name              |in_belongsTo|out   |in    |out_belongsTo
----+------+---------+------------------+------------+------+------+-------------
0   |#11:0 |Level01  |Item01_at_Level01 |[size=2]    |null  |null  |null
1   |#20:1 |belongsTo|null              |null        |#12:1 |#11:0 |null
2   |#12:1 |Level02  |Item02_at_Level02 |[size=2]    |null  |null  |[size=1]
3   |#20:4 |belongsTo|null              |null        |#13:0 |#12:1 |null
4   |#13:0 |Level03  |Item01_at_Level03 |[size=2]    |null  |null  |[size=1]
5   |#20:19|belongsTo|null              |null        |#14:7 |#13:0 |null
6   |#14:7 |Level04  |Item08_at_Level04 |[size=2]    |null  |null  |[size=1]
7   |#20:34|belongsTo|null              |null        |#15:6 |#14:7 |null
8   |#15:6 |Level05  |Item07_at_Level05 |null        |null  |null  |[size=1]
9   |#20:50|belongsTo|null              |null        |#15:22|#14:7 |null
10  |#15:22|Level05  |Item023_at_Level05|null        |null  |null  |[size=1]
11  |#20:27|belongsTo|null              |null        |#14:15|#13:0 |null
12  |#14:15|Level04  |Item016_at_Level04|[size=2]    |null  |null  |[size=1]
13  |#20:42|belongsTo|null              |null        |#15:14|#14:15|null
14  |#15:14|Level05  |Item015_at_Level05|null        |null  |null  |[size=1]
15  |#20:58|belongsTo|null              |null        |#15:30|#14:15|null
16  |#15:30|Level05  |Item031_at_Level05|null        |null  |null  |[size=1]
17  |#20:8 |belongsTo|null              |null        |#13:4 |#12:1 |null
18  |#13:4 |Level03  |Item05_at_Level03 |[size=2]    |null  |null  |[size=1]
19  |#20:15|belongsTo|null              |null        |#14:3 |#13:4 |null
----+------+---------+------------------+------------+------+------+-------------
LIMIT EXCEEDED: resultset contains more items not displayed (limit=20)

The only property I have on any nodes is name . I seem to recall that I could filter out the belongsTo edges (or at least only look for specific classes), but I've switched to trying a fetchPlan so I can get a nested JSON blob returned instead. That query is easy enough (`, but I'm trying to figure out how best to limit the depth and not actually return the edges as part of the result.

Here's that query and result in console (same in studio): orientdb {db=FetchPlanTesting}> SELECT @this.toJSON('fetchPlan:*:-1') from 11:0

----+------+--------------------------------------------------------------------------------------------------------------------------------------------
#   |@CLASS|this
----+------+--------------------------------------------------------------------------------------------------------------------------------------------
0   |null  |{"name":"Item01_at_Level01","in_belongsTo":[{"out":{"name":"Item02_at_Level02","in_belongsTo":[{"out":{"name":"Item01_at_Level03","in_bel...
----+------+--------------------------------------------------------------------------------------------------------------------------------------------

1 item(s) found. Query executed in 0.024 sec(s).