Cypher Language Overview

The implementation of Cypher in Graph Lakehouse closely follows the openCypher community group's version 9 specification of the Cypher language. (See the openCypher Resource page available at https://www.opencypher.org/resources/. An Acrobat PDF copy of the Cypher Query Language Reference is available at https://s3.amazonaws.com/artifacts.opencypher.org/openCypher9.pdf.

Some Cypher features, based on the version 9 openCypher specification of the Cypher language, are not yet supported in Graph Lakehouse:

• Uniqueness
• Cypher statements with interleaving of read and update clauses
• The Merge clause
• Relational and concatenation operators on list and map types
• The Unwind clause with list variables
• Path variable and variable length pattern matching
• Graph Lakehouse UDX and graph algorithms support
• Parameters

For users of previous Graph Lakehouse releases, support for the following new features was added for Graph Lakehouse Version 2.4 and later releases:

• List and map type support
• The Collect() aggregate
• Functions operating on list and map types
• List comprehension
• Property chaining and dynamic property access with the '[ ]' operator
• Improved node/relationship variables handling in complex expressions

To use Cypher in Graph Lakehouse, queries and other statements can be sent over the Bolt client-server network protocol to Graph Lakehouse servers. Graph Lakehouse supports Bolt protocol, version 1.0. Port 7088 is the default port used for the Bolt end-point. The azgbolt CLI provides a simple way to send Cypher queries to Graph Lakehouse over the Bolt protocol. For example:

azgbolt -f query.cql azgbolt -c "match (m:Movie) return m"

Graph data can be queried with SPARQL as well as Cypher language statements; both query modes can co-exist. The Graph Lakehouse Bolt protocol can also be used to execute SPARQL queries, however, in that case, support for various data types in results returned from queries is limited.

For a brief introduction to using Cypher in Graph Lakehouse, see Working with Cypher and the Movie Data.

In Cypher, CREATE statements can be used to load graph data into Graph Lakehouse, which is convenient for loading smaller data sets. For bulk loading of larger RDF/RDF* data sets or non-RDF data, see Load & Manage Data for more information.

Cypher node and relationship data is represented in RDF* triples format as illustrated in the following example.

Cypher CREATE statements:

CREATE (TheMatrix:Movie {title:'The Matrix', released:1999, tagline:'Welcome to the Real World'}) CREATE (Keanu:Person {name:'Keanu Reeves', born:1964}) CREATE (Keanu)-[:ACTED_IN {role:'Neo'}]->(TheMatrix)

RDF* triple format of data stored in Graph Lakehouse:

@prefix rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns# . rdf:type .