[Neo4j] Cypher questions
Hello,
I have some questions regarding Cypher.
1. I have an ontology that defines classes and individuals. I store this
ontology into Neo4J REST db. Is there any ways to find all individuals that
have some given class?
In SPARQL, it can be done like ...WHERE { ?u a :User.}... to find all
instances that have a type of User.
2. Similar to the question#1, if I understand correctly in Cypher I always have
to start with a known node either by its ID or name. If so how to find any
nodes that have some given relationship?
For example, I want to find any nodes that have the the relationship type
go_to_school.
(x)-[:go_to_school]-(n) where (n.name= NotreDame) return x
Thank you,
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Re: [Neo4j] Cypher questions
Both your questions would be answered with indexing:
for the 1) you would add the user nodes them to a User index and then use
start user=node:User(id:*) ...
For 2) you would index the relationships-similarly (for the interesting types).
e.g. create an index for only the rel-type you're interested in:
index().forRelationships(go_to_school).add(rel, key,value) key and value
are arbitrary things, but you might leverage them with sensible data in your
domain model.
start r = relationship:go_to_school(field:*) match (x)-[r]-(n) where n.name
= Notre Dame return x
!! usually you would probably rather index the schools, and look them up
directly
start school = node:schools(name,{school_name}) match
pupil-[:go_to_school]-school return pupil
(You could use auto-indexing for both if that is useful for you, the
index-names would then be node_auto_index and relationship_auto_index, see :
http://docs.neo4j.org/chunked/snapshot/auto-indexing.htmlhttp://docs.neo4j.org/chunked/snapshot/rest-api-auto-indexes.html
)
Am 03.11.2011 um 00:35 schrieb andrew ton:
Hello,
I have some questions regarding Cypher.
1. I have an ontology that defines classes and individuals. I store this
ontology into Neo4J REST db. Is there any ways to find all individuals that
have some given class?
In SPARQL, it can be done like ...WHERE { ?u a :User.}... to find all
instances that have a type of User.
2. Similar to the question#1, if I understand correctly in Cypher I always
have to start with a known node either by its ID or name. If so how to find
any nodes that have some given relationship?
For example, I want to find any nodes that have the the relationship type
go_to_school.
(x)-[:go_to_school]-(n) where (n.name= NotreDame) return x
Thank you,
___
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User@lists.neo4j.org
https://lists.neo4j.org/mailman/listinfo/user
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Re: [Neo4j] Cypher questions
Andrew,
we have been trying to keep things very tight and document most of the
functionality in the manual. See even some domain examples that have
Cypher in them,
http://docs.neo4j.org/chunked/snapshot/domain-modeling-gallery.html
What else would you like to see?
Cheers,
/peter neubauer
GTalk: neubauer.peter
Skype peter.neubauer
Phone +46 704 106975
LinkedIn http://www.linkedin.com/in/neubauer
Twitter http://twitter.com/peterneubauer
http://www.neo4j.org - NOSQL for the Enterprise.
http://startupbootcamp.org/ - Öresund - Innovation happens HERE.
On Wed, Nov 2, 2011 at 7:32 PM, andrew ton andrewt...@yahoo.com wrote:
Hi Michael,
Thank you very much! Your answers are very helpful to me. Although I have
read the manual enclosed in the neo4j package I downloaded I did not know
that we can use * wildcard for any ids or names.
Besides the manual what other resources can I find to understand more about
Cypher?
Appreciated your help.
A.
From: Michael Hunger michael.hun...@neotechnology.com
To: Neo4j user discussions user@lists.neo4j.org
Sent: Wednesday, November 2, 2011 5:31 PM
Subject: Re: [Neo4j] Cypher questions
Both your questions would be answered with indexing:
for the 1) you would add the user nodes them to a User index and then use
start user=node:User(id:*) ...
For 2) you would index the relationships-similarly (for the interesting
types).
e.g. create an index for only the rel-type you're interested in:
index().forRelationships(go_to_school).add(rel, key,value) key and
value are arbitrary things, but you might leverage them with sensible data in
your domain model.
start r = relationship:go_to_school(field:*) match (x)-[r]-(n) where
n.name = Notre Dame return x
!! usually you would probably rather index the schools, and look them up
directly
start school = node:schools(name,{school_name}) match
pupil-[:go_to_school]-school return pupil
(You could use auto-indexing for both if that is useful for you, the
index-names would then be node_auto_index and relationship_auto_index, see :
http://docs.neo4j.org/chunked/snapshot/auto-indexing.htmlhttp://docs.neo4j.org/chunked/snapshot/rest-api-auto-indexes.html
)
Am 03.11.2011 um 00:35 schrieb andrew ton:
Hello,
I have some questions regarding Cypher.
1. I have an ontology that defines classes and individuals. I store this
ontology into Neo4J REST db. Is there any ways to find all individuals that
have some given class?
In SPARQL, it can be done like ...WHERE { ?u a :User.}... to find all
instances that have a type of User.
2. Similar to the question#1, if I understand correctly in Cypher I always
have to start with a known node either by its ID or name. If so how to find
any nodes that have some given relationship?
For example, I want to find any nodes that have the the relationship type
go_to_school.
(x)-[:go_to_school]-(n) where (n.name= NotreDame) return x
Thank you,
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___
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https://lists.neo4j.org/mailman/listinfo/user
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Re: [Neo4j] Cypher questions
the Neo4j-indexing provider (which is also used by Cypher) is lucene, so the
default lucene query syntax works in the neo4j core API and Cypher queries.
http://lucene.apache.org/java/3_4_0/queryparsersyntax.html
Michael
Am 03.11.2011 um 03:32 schrieb andrew ton:
Hi Michael,
Thank you very much! Your answers are very helpful to me. Although I have
read the manual enclosed in the neo4j package I downloaded I did not know
that we can use * wildcard for any ids or names.
Besides the manual what other resources can I find to understand more about
Cypher?
Appreciated your help.
A.
From: Michael Hunger michael.hun...@neotechnology.com
To: Neo4j user discussions user@lists.neo4j.org
Sent: Wednesday, November 2, 2011 5:31 PM
Subject: Re: [Neo4j] Cypher questions
Both your questions would be answered with indexing:
for the 1) you would add the user nodes them to a User index and then use
start user=node:User(id:*) ...
For 2) you would index the relationships-similarly (for the interesting
types).
e.g. create an index for only the rel-type you're interested in:
index().forRelationships(go_to_school).add(rel, key,value) key and
value are arbitrary things, but you might leverage them with sensible data in
your domain model.
start r = relationship:go_to_school(field:*) match (x)-[r]-(n) where
n.name = Notre Dame return x
!! usually you would probably rather index the schools, and look them up
directly
start school = node:schools(name,{school_name}) match
pupil-[:go_to_school]-school return pupil
(You could use auto-indexing for both if that is useful for you, the
index-names would then be node_auto_index and relationship_auto_index, see :
http://docs.neo4j.org/chunked/snapshot/auto-indexing.htmlhttp://docs.neo4j.org/chunked/snapshot/rest-api-auto-indexes.html
)
Am 03.11.2011 um 00:35 schrieb andrew ton:
Hello,
I have some questions regarding Cypher.
1. I have an ontology that defines classes and individuals. I store this
ontology into Neo4J REST db. Is there any ways to find all individuals that
have some given class?
In SPARQL, it can be done like ...WHERE { ?u a :User.}... to find all
instances that have a type of User.
2. Similar to the question#1, if I understand correctly in Cypher I always
have to start with a known node either by its ID or name. If so how to find
any nodes that have some given relationship?
For example, I want to find any nodes that have the the relationship type
go_to_school.
(x)-[:go_to_school]-(n) where (n.name= NotreDame) return x
Thank you,
___
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https://lists.neo4j.org/mailman/listinfo/user
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