Accessing graph data in Amazon Neptune

You can interact with a Amazon Neptune db cluster after created set up connection. This involves loading data, executing queries, and performing other operations. Most users leverage the curl or awscurl command-line tools to communicate with the Neptune DB cluster effectively. These tools enable you to send requests, load data, and retrieve results from the graph database, facilitating seamless data management and querying capabilities.

Setting up curl to communicate with your Neptune endpoint

As illustrated in many of the examples in this documentation, the curl command line tool is a handy option for communicating with your Neptune endpoint. For information about the tool, see the curl man page, and the book Everything curl.

To connect using HTTPS (as we recommend and as Neptune requires in most Regions), curl needs access to appropriate certificates. To learn how to obtain these certificates and how to format them properly into a certificate authority (CA) certificate store that curl can use, see SSL Certificate Verification in the curl documentation.

You can then specify the location of this CA certificate store using the CURL_CA_BUNDLE environment variable. On Windows, curl automatically looks for it in a file named curl-ca-bundle.crt. It looks first in the same directory as curl.exe and then elsewhere on the path. For more information, see SSL Certificate Verification.

As long as curl can locate the appropriate certificates, it handles HTTPS connections just like HTTP connections, without extra parameters. Examples in this documentation are based on that scenario.

Using a query language to access graph data in your Neptune DB cluster

Once you are connected, you can use the Gremlin and openCypher query languages to create and query a property graph, or the SPARQL query language to create and query a graph containing RDF data.

Graph query languages supported by Neptune

• Gremlin is a graph traversal language for property graphs. A query in Gremlin is a traversal made up of discrete steps, each of which follows an edge to a node. See Gremlin documentation at Apache TinkerPop3 for more information.

  The Neptune implementation of Gremlin has some differences from other implementations, especially when you are using Gremlin-Groovy (Gremlin queries sent as serialized text). For more information, see Gremlin standards compliance in Amazon Neptune.

• openCypher is a declarative query language for property graphs that was originally developed by Neo4j, then open-sourced in 2015, and contributed to the openCypher project under an Apache 2 open-source license. Its syntax is documented in the Cypher Query Language Reference, Version 9.

• SPARQL is a declarative query language for RDF data, based on the graph pattern matching that is standardized by the World Wide Web Consortium (W3C) and described in SPARQL 1.1 Overview) and the SPARQL 1.1 Query Language specification.

Note

You can access property graph data in Neptune using both Gremlin and openCypher, but not using SPARQL. Similarly, you can only access RDF data using SPARQL, not Gremlin or openCypher.