World Library  
Flag as Inappropriate
Email this Article

Cypher Query Language

 

Cypher Query Language

Cypher is a declarative graph query language for the graph database, Neo4j that allows for expressive and efficient querying and updating of the graph store. Cypher is a relatively simple but still very powerful language. Very complicated database queries can easily be expressed through Cypher. This allows users to focus on their domain instead of getting lost in database access.[1]

Syntax

Cypher contains a variety of clauses. Among the most common are: MATCH and WHERE. These functions are slightly different than in SQL. MATCH is used for describing the structure of the pattern searched for, primarily based on relationships. WHERE is used to add additional constraints to patterns. For example:[2]

    MATCH (charlie:Person { name:'Charlie Sheen' })-[:ACTED_IN]-(movie:Movie)
    RETURN movie

Cypher additionally contains clauses for writing, updating, and deleting data. CREATE and DELETE are used to create and delete nodes and relationships. SET and REMOVE are used to set values to properties and add labels on nodes. It should be noted that nodes can only be deleted when they have no other relationships still existing. For example:[2]

    MATCH (start:Content)-[:RELATED_CONTENT]->(content:Content)
    WHERE content.source = 'user'
    OPTIONAL MATCH (content)-[r]-()
    DELETE r, content

See also

  • SPARQL, another declarative query language for querying graph data
  • OpenCypher, an initiative by Neo4j and others to extend the use of cypher to other graph databases[3]

References

  1. ^
  2. ^ a b
  3. ^ http://neo4j.com/blog/open-cypher-sql-for-graphs/
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.