I am importing data from SQL Server to Cosmos Gremlin Graph. During the process, I need to search for a vertex by its old id, as the new id is needed to create an edge. I only want the id not all the other properties.
I found the answer.
You can use the SubmitWithSingleResultAsync( query ); method with a query like g.V().has('elementTypeId','1').has('importId',123456).properties('id').value()
Related
I'm trying to execute an OLAP traversal on a query that needs to check if a vertex has a neighbour of certain type.
i keep getting
Local traversals may not traverse past the local star-graph on GraphComputer
my query looks something like:
g.V().hasLabel('label1').
where(_.out().hasLable('label2'))
I'm using the TraversalVertexProgram.
needless to say, when running the same query in oltp mode there is no problem
is there a way to execute such logic?
That is limitation of TinkerPop OLAP GraphComputer. It operate on 'star-graph' objects. The vertex and connected edges only. It uses message passing engine inside. So you have to rewrite you query.
Option 1: start from label2 and go t label1. This should return the same result
g.V().hasLabel('label2').in().hasLabel('label1')
Option2: try to use unique edge labels and check edge label instead
g.V().hasLabel('label1').where(_.outE('label1_label2'))
I want to create 1000+ Edges in a single query.
Currently, I am using the AWS Neptune database and gremlin.net for creating it.
The issue I am facing is related to the speed. It took huge time because of HTTP requests.
So I am planning to combine all of my queries in a string and executing in a single shot.
_g.AddE("allow").From(_g.V().HasLabel('person').Has('name', 'name1')).To(_g.V().HasLabel('phone').Where(__.Out().Has('sensor', 'nfc'))).Next();
There are chances that the "To" (target) Vertex may not be available in the database. When it is the case this query fails as well. So I had to apply a check if that vertex exists before executing this query using hasNext().
So as of now its working fine, but when I am thinking of combining all 1000+ edge creation at once, is it possible to write a query which doesn't break if "To" (target) Vertex not found?
You should look at using the Element Existence pattern for each vertex as shown in the TinkerPop Recipes.
In your example you would replace this section of your query:
_g.V().HasLabel('person').Has('name', 'name1')
with something like this (I don't have a .NET environment to test the syntax):
__.V().Has('person', 'name', 'name1').Fold().
coalesce(__.Unfold(), __.AddV('person').Property('name', 'name1')
This will act as an Upsert and either return the existing vertex or add a new one with the name property. This same pattern can then be used on your To step to ensure that it exists before the edge is created as well.
Using Azure's Cosmos DB Graph Database I have a sample DB:Sample Graph Database. I am trying to expand a simple query into one that returns all the "Person" Nodes that have a "Skill Ratings" Node where MS_OFFICE=FAIL AND .NET=TRUE.
Current Query Thus Far:
ENGLISH DESCRIPTION: Find "Person Nodes" whose "Skill Ratings" Node match MS_OFFICE=FAIL
GREMLIN QUERY: g.V().hasLabel("Person").as("PersonNode")
.out("scored").as("SkillNode")
.has("skill_Name","MS_OFFICE")
.has("skill_Value","FAIL")
.select("PersonNode").by("Name")
To modify the existing query to include a conditional element, I was wondering if I am just missing a specific traversal step in the TinkerPop Documentation?
I think you just need something like this:
g.V().hasLabel("Person").
where(out("scored").
has("skill_name","MS_OFFICE").
has('skill_value","FAIL")).
values('name')
Is Label Name in Gremlin Cosmos DB, Case Sensitive? For example is g.V().hasLabel('User') different with g.V().hasLabel('user')?
Yes. it is. You can test it by adding some instances to the database. For example:
g.addV('User');
g.addV('User');
g.addV('User');
Then get query by g.V().hasLabel('user'), the result will be null.
I'm trying to create user Notification whenever any user comments on user's post.
i'm using following gremlin query -
g.v(512).outE('Notification').order{it.b.PostedDate <=> it.a.PostedDate}[0..3].transform{ [notificationInfo:it,postInfo:it.inV]}
and am getting following result -
Am getting NotificationInitiatedByVertexId value in edge. how can I use that vertex id (ie. NotificationInitiatedByVertexId: 1280) to get information about the vertex in the same query result.
I would suggest trying to add it to the transform statement you already have:
g.v(512).outE('Notification').order{it.b.PostedDate <=> it.a.PostedDate}[0..3].transform{ [notificationInfo:it,postInfo:it.inV,notifiedV:g.v(it.NotificationInitiatedByVertexId)]}