When I run a query I can see the nodes correctly. But I need to go one by one and click "Expand child relationships" which is tedious and time consuming. Is there any way to see the graph with everything already expanded?
Thanks!
You're talking about Neo4j Browser, right?
If so, you need to specify exactly what you need to visualize first. So let's say you have a User node that is connected to a Book node with a read relationship.
Instead of just
MATCH (u:User)
RETURN u
And expanding that node to see all other connected nodes, just do
MATCH (u:User)-[:read]->(b:Book)
RETURN *
And just add the relationships you want in the query itself.
You can, however, do
MATCH (n) RETURN n
Which will return every node with its relationship, but there's a limit to how many nodes you can see. You can extend the limit in the settings (bottom left of the navigation bar) and tinkering with Graph Visualization values. This is not recommended and, depending on the size of your graphdb, it could cause a bottleneck and it can take a lot of time.
My advice, just write a query that shows exactly which nodes and relationships you want to see.
The Neo4j Browser supports an "auto-completion" mode that, when enabled, automatically queries for (and displays) the relationships between the nodes returned by a Cypher query.
In the most recent versions of the Browser, you can enable auto-completion mode by clicking the gear icon on the left side, scrolling to the bottom of the Browser Settings panel, and check-marking the "Connect result nodes" option.
Related
I have 565 articles in Neo4j and I ran LPA to obtain clusters.
I have the following result: 69 communities.
I would like to display all the communities at the same time in Neo4j.
I tried several Cypher queries with the property key 'community' but it didn't work.
My data looks like this:
How can I do it ?
Presumably, you are using the neo4j Browser to visualize your results.
When your Cypher query returns any nodes, relationships, or paths, the browser will automatically show you the Graph view (on the left side of the result panel, you should see icons with captions that may include Graph, Table, Text, etc.). The Graph view only shows nodes and relationships, and not anything else that was returned.
However, if you click on the other icons (say, Table or Text), you should see more results -- like the communities, presented in different formats.
By the way, specifying the node label would make your query more efficient (and adding an index would make it even more efficient if you have a lot of ARTICLE nodes):
MATCH (n:ARTICLE) WHERE EXISTS(n.community)
RETURN n, n.community
I deleted all of node and relationship. Now, I want to delete all existing labels with a Cypher query but I can't.
You are probably referring to the neo4j browser's "Node labels" display. The browser can continue to display labels that have been deleted from all nodes (or even if the DB no longer has any nodes). This is really just a minor nuisance.
As long as your Cypher queries show that there are no nodes with that label, rest assured that the label does not "really" exist in the DB.
If you're removing all of the data (nodes and relationships) anyway, you might as well delete your graph.db directory or wherever you store your data. This will also result in having pre-existing labels not show up in the browser.
This will also remove all indexes you might have had set up.
I'm building a Neo4J system just do to visualization in the Neo4J browser. I build the various nodes and relationships and I can visualize the database by running match (n) return n. The problem is that the resulting display shows the relationship names but not their associated properties. Can anyone tell me the cypher query to show the entire database including relationship properties? Thanks.
The neo4j browser does not support visualizing all properties (for nodes or relationships) at the same time. Such a capability would generally result in a very congested and unusable visualization, especially since the browser would also have to display the property names.
You can, however, opt to show the value of a single property per node label or or relationship type as its caption. You can do that manually, or you can edit the GRASS file to set all of the captions at once. As an example of how to set relationship captions in the GRASS file, the following entry in that file would specify that all BAR relationships should show their foo property:
relationship.BAR {
caption: '{foo}';
}
I want to change the color of my nodes based on their properties:
Say I have many "Person" nodes. And I want those who live in New York to be red and those who live in Los Angeles to be blue. How would I write that. In cypher or in py2neo?
The styling of nodes and relationships in Neo4j Browser is controlled by a graph style sheet (GRASS), a cousin of CSS. You can view the current style by typing :style in the browser. To edit it, you can click on nodes and relationships and pick colors and sizes, or you can view the style sheet (:style), download it, make changes, and drag-n-drop it back into the view window.
Unfortunately for your case, color can only be controlled a) for all nodes and all relationships or b) for nodes by label and relationships by type. Properties can only be used for the text displayed on the node/rel.
It is not possible to interact with neo4j browser pro-grammatically. But the end goal could be achieved through a hack.
Even though I am a bit late here want to help others who might be finding a way. It is not possible to change the color of the nodes based on the property but there is a way it can be achieved by creating nodes based on the property. Keep in mind that after applying these queries your data wont be the same. So it is always a good idea to keep a backup of your data.
This is how labels are colored by default (Before):
Color based on the property
Suppose there is a label called Case with a property nationality and you want to color the nodes based on nationality. So following query could be used to create labels out of nationality property. For this you will need to install apoc library. check here for installation.
// BY NATIONALITY
MATCH (n:Case)
WITH DISTINCT n.nationality AS nationality, collect(DISTINCT n) AS persons
CALL apoc.create.addLabels(persons, [apoc.text.upperCamelCase(nationality)]) YIELD node
RETURN *
This will return all the people by nationality. Now you can color by country of nationality. Below shows an example.
Color based on the property and load with other labels
Lets say you also have a label called Cluster.The cases are attached to clusters via relationships. Just change the query to following to get the clusters with their relationships to cases.
//BY NATIONALITY WITH CLUSTERS
MATCH (n:Case),(c:Cluster)
WITH DISTINCT n.nationality AS nationality,
collect(DISTINCT n) AS persons,
collect(DISTINCT c) AS clusters
CALL apoc.create.addLabels(persons, [apoc.text.upperCamelCase(nationality)]) YIELD node
RETURN *
It will return cases and clusters with all the relationships. Below shows example.
Please leave an up vote if this was helpful and want to let others know that this is an acceptable answer. Thank you.
You cannot include formatting of the output in Cypher queries in the neo4j browser. Currently, the only way is to change the graph view manually or load a graph style file.
See tutorial here: http://neo4j.com/developer/guide-neo4j-browser/
Also, you cannot interact with the neo4j browser from py2neo.
If you are happy setting the color through a graphical user interface rather than programatically, Neo4j also supplies a data exploration addon named bloom. When using this addon (now automatically installed when using neo4j desktop), it is possible to set node color based on its properties.
In the example below, movies released after 2002 are colored green.
The answer to this question shows how to get a list of all nodes connected to a particular node via a path of known relationship types.
As a follow up to that question, I'm trying to determine if traversing the graph like this is the most efficient way to get all nodes connected to a particular node via any path.
My scenario: I have a tree of groups (group can have any number of children). This I model with IS_PARENT_OF relationships. Groups can also relate to any other groups via a special relationship called role playing. This I model with PLAYS_ROLE_IN relationships.
The most common question I want to ask is MATCH(n {name: "xxx") -[*]-> (o) RETURN o.name, but this seems to be extremely slow on even a small number of nodes (4000 nodes - takes 5s to return an answer). Note that the graph may contain cycles (n-IS_PARENT_OF->o, n<-PLAYS_ROLE_IN-o).
Is connectedness via any path not something that can be indexed?
As a first point, by not using labels and an indexed property for your starting node, this will already need to first find ALL the nodes in the graph and opening the PropertyContainer to see if the node has the property name with a value "xxx".
Secondly, if you now an approximate maximum depth of parentship, you may want to limit the depth of the search
I would suggest you add a label of your choice to your nodes and index the name property.
Use label, e.g. :Group for your starting point and an index for :Group(name)
Then Neo4j can quickly find your starting point without scanning the whole graph.
You can easily see where the time is spent by prefixing your query with PROFILE.
Do you really want all arbitrarily long paths from the starting point? Or just all pairs of connected nodes?
If the latter then this query would be more efficient.
MATCH (n:Group)-[:IS_PARENT_OF|:PLAYS_ROLE_IN]->(m:Group)
RETURN n,m