Here I have created a manual/legacy index and added some nodes with certain properties into it.
IndexManager indexy = graphdb.index();
Index<Node>indexery = indexy.forNodes("Main_Twitter_Index");
indexery.add(one,"Name",one.getProperty("Name"));
indexery.add(one,"Email",one.getProperty("Email"));
indexery.add(four,"Name",four.getProperty("Name"));
indexery.add(four,"Email",four.getProperty("Email"));
Now, to query the nodes of that index neo4j suggests query, which uses a key-value pair binding. My question is can I query the same nodes added into the manual index using a simple cypher query like,
START n=node:Main_Twitter_Index(Name = 'Akina')
RETURN n
Which version of Neo4j are you using? The method you describe is the typical index search for anything before 2.0, before they added schema indexing. Your query should work, even in 2.0. Are you having problems running it?
Related
I m trying to sort the AEM query builder search results based on particular value of particular property. as we have in any database like MySQL we can sort based on column's value as well (for exp. ORDER BY FIELD('columnName','anyColumnName'). can we have something like this in AEM.
Suppose we have 5 Assets under path /content/dam/Assets.
Asset Name------------dc:title
1.jpg------------------Apple
2.jpg------------------Cat
3.jpg------------------Cat
4.jpg------------------Ball
5.jpg------------------Drag
I need assets on top of the results where dc:title = cat and also need other results also in sorting asc. expected result as given below
2.jpg------------------Cat
3.jpg------------------Cat
1.jpg------------------Apple
4.jpg------------------Ball
5.jpg------------------Drag
Note:- Using version AEM 6.2
You can use the orderby predicate with a value of #jcr:content/metadata/dc:title to sort by dc:title with the QueryBuilder. /libs/cq/search/content/querydebug.html is an interface to test queries on your instance. ACS Commons has a good breakdown of all out of the box predicates
If you want to pull Cats to the top of the results with a single query, you could write a custom predicate. The sample code from ACS Commons shows an example. Adobe has documentation as well.
I'm using neo4j-jdbc 2.3.2 as my neo4j client for java. When I executed following cypher query
match(p:Person) where p.id_number='761201948V' return p.id; it will return P2547228 as node id. I feel like id is same as other properties of the node as I can use it inside where clauses. But here I'm expecting an integer which can use inside this query START p=node('node.id') return p; Is this id is an internal thing to neo4j db? and is there a way to retrieve this id?
From the following two cyphers what is most efficient one?(if both referring same node)
START p=node('2547223') return p;
match(p:Person) where p.id='P2547228' return p;
You have to use the ID(x) function for this. Note, that ID(x) and x.id are a complete different thing. The former returns the internal node/relationship id managed by Neo4j itself. The latter gives the id property which is managed by the user and not by the database itself.
Also note, that a node/relationship ID is always numeric.
Using START is pretty much old school and shouldn't be used any more (except for accessing manual indexes):
start p=node(2547228) return p
This one is a equivalent statement. It is highly efficient since it just needs to do a simple seek operation on the node store:
match(p:Person) where id(p)=2547228 return p;
Looking for a property requires either a node label scan or a schema index lookup:
match(p:Person) where p.id=2547228 return p;
Just check out the query plans on your own by prefixing the statement with PROFILE.
In my Java code I have a query to match the shortest path from root to a leaf in my tree.
Strinq query = "Match path = (p:Root)-[*1..100]-(m:Leaf) "
+ "WITH p,m,path ORDER BY length(path) LIMIT 1 RETURN path";
However, when I try to query this as follows
SessionFactory sessionFactory = new SessionFactory("incyan.Data.Neo4j.Models");
Session session = sessionFactory.openSession("http://localhost:7474");
Object o = session(query, new HashMap<String,Object>());
o contains an ArrayList of LinkedHashMaps instead of mapped objects.
I cannot even determine the labels of the path elements and the start and end nodes of the relations.
What am I doing wrong?
The current neo4j-ogm release does not map query results to domain entities. Returning a path will only give you the properties of nodes and relationships in that path (in order, so you can infer the relationship start/end). ID's aren't returned by the Neo4j REST api currently used by the OGM for this particular operation and that's why they are missing. You may instead have to extract the ID's and return them as part of your query.
Mapping individual query result columns to entities will be available in a Neo4j-OGM 2.0 release.
I'm not sure about the Java bit, but if you use the shortestPath function (keyword?) your query should be more efficient:
MATCH path=shortestPath((p:Root)-[*1..100]-(m:Leaf))
RETURN path
Also, I don't know what your data model is like, but I would expect the labels on the nodes of your tree (I'm assuming it's a tree) to all be the same. You can tell if a node is a root or a leaf using Cypher:
MATCH path=shortestPath((root:Element)-[*1..100]-(leaf:Element))
WHERE NOT((root)-[:HAS_PARENT]->()) AND NOT(()-[:HAS_PARENT]->(leaf))
RETURN path
I have a huge graphdatabase with authors, which are connected to papers and papers a connected to nodes which contains meta information of the paper.
I tried to select authors which match a specific pattern and therefore I executed the following cypher statement in java.
String query = "MATCH (n:AUTHOR) WHERE n.name =~ '(?i).*jim.*' RETURN n";
db.execute(query);
I get a resultSet with all "authors" back. But the execution is very slow. Is it, because Neo4j writes the result into the memory?
If I try to find nodes with the Java API, it is much faster. Of course, I am only able to search for the exact name like the following code example, but it is about 4 seconds faster as the query above. I tested it on a small database with about 50 nodes, whereby only 6 of the nodes are authors. The six author are also in the index.
db.findNodes(NodeLabel.AUTHOR, NodeProperties.NAME, "jim knopf" );
Is there a chance to speed up the cypher? Or a possiblity to get all nodes via Java API and the findNodes() method, which match a given pattern?
Just for information, I created the index for the name of the author in java with graph.schema().indexFor(NodeLabel.AUTHOR).on("name").create();
Perhaps somebody could help. Thanks in advance.
EDIT:
I run some tests today. If I execute the query PROFILE MATCH (n:AUTHOR) WHERE n.name = 'jim seroka' RETURN n; in the browser interface, I have only the operator NodeByLabelScan. It seems to me, that Neo4j does not automatic use the index (Index for name is online). If I use a the specific index, and execute the query PROFILE MATCH (n:AUTHOR) USING INDEX n:AUTHOR(name) WHERE n.name = 'jim seroka' RETURN n; the index will be used. Normally Neo4j should use automatically the correct index. Is there any configuration to set?
I also did some testing in the embedded mode again, to check the performance of the query in the embedded mode. I tried to select the author "jim seroka" with db.findNode(NodeLabel.AUTHOR, "name", "jim seroka");. It works, and it seems to me that the index is used, because of a execution time of ~0,05 seconds.
But if I run the same query, as I executed in the interface and mentioned before, using a specific index, it takes ~4,9 seconds. Why? I'm a little bit helpless. The database is local and there are only 6 authors. Is the connector slow or is the creation of connection wrong? OK, findNode() does return just a node and execute a whole Result, but four seconds difference?
The following source code should show how the database will be created and the query is executed.
public static GraphDatabaseService getNeo4jDB() {
....
return new GraphDatabaseFactory().newEmbeddedDatabase(STORE_DIR);
}
private Result findAuthorNode(String searchValue) {
db = getNeo4jDB();
String query = "MATCH (n:AUTHOR) USING INDEX n:AUTHOR(name) WHERE n.name = 'jim seroka' RETURN n";
return db.execute(query);
}
Your query uses a regular expression and therefore is not able to use an index:
MATCH (n:AUTHOR) WHERE n.name =~ '(?i).*jim.*' RETURN n
Neo4j 2.3 introduced index supported STARTS WITH string operator so this query would be very performant:
MATCH (n:Author) WHERE n.name STARTS WITH 'jim' RETURN n
Not quite the same as the regular expression, but will have better performance.
I have a solr field visibility that has a set of possible values and I would like to perform a search using Spring Data Solr. I'd like to use in() and boost some but not all values if possible.
Here's an example of the search I need,
visibility:(visible^1000 archived)
or
visibility:(visible^1000 draft^500 archived)
Would this be possible in version 1.0.0.RELEASE or later versions? Currently I'm using 1.0.0.RELEASE.
Thanks, /w
I never managed to chain this query properly, but was enlightened by petrikainulainen.net on SimpleStringCriteria().
Criteria criteria = new SimpleStringCriteria("(visibility:(visible^1000) OR visibility:(draft^500) OR visibility:(archived))");
By doing as shown below you will give far higher boost to the docs that has the category as 'webpage'. Then add 'combined' criteria to your existing other criteria
Criteria webpage= new Criteria("category" ).is("webpage" ).boost((float) 1000);
Criteria document= new Criteria("category" ).is("document" ).boost((float) 2);
Criteria combined= webpage.or( document);