Creating a Neptune GraphMappingConfig - Amazon Neptune
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Creating a Neptune GraphMappingConfig

The GraphMappingConfig that you create specifies how data extracted from a source data store should be loaded into a Neptune DB cluster. Its format differs depending on whether it is intended for loading RDF data or for loading property-graph data.

For RDF data, you can use the W3 R2RML language for mapping relational data to RDF.

If you are loading property-graph data to be queried using Gremlin, you create a JSON object for GraphMappingConfig.

GraphMappingConfig Layout for RDF/SPARQL Data

If you are loading RDF data to be queried using SPARQL, you write the GraphMappingConfig in R2RML. R2RML is a standard W3 language for mapping relational data to RDF. Here is one example:

@prefix rr: <http://www.w3.org/ns/r2rml#> . @prefix ex: <http://example.com/ns#> . <#TriplesMap1> rr:logicalTable [ rr:tableName "nodes" ]; rr:subjectMap [ rr:template "http://data.example.com/employee/{id}"; rr:class ex:Employee; ]; rr:predicateObjectMap [ rr:predicate ex:name; rr:objectMap [ rr:column "label" ]; ] .

Here is another example:

@prefix rr: <http://www.w3.org/ns/r2rml#> . @prefix ex: <http://example.com/#> . @prefix foaf: <http://xmlns.com/foaf/0.1/> . @prefix xsd: <http://www.w3.org/2001/XMLSchema#> . <#TriplesMap2> rr:logicalTable [ rr:tableName "Student" ]; rr:subjectMap [ rr:template "http://example.com/{ID}{Name}"; rr:class foaf:Person ]; rr:predicateObjectMap [ rr:predicate ex:id ; rr:objectMap [ rr:column "ID"; rr:datatype xsd:integer ] ]; rr:predicateObjectMap [ rr:predicate foaf:name ; rr:objectMap [ rr:column "Name" ] ] .

The W3 Recommendation at R2RML: RDB to RDF Mapping Language provides details of the language.

GraphMappingConfig Layout for Property-Graph/Gremlin Data

A comparable GraphMappingConfig for property-graph data is a JSON object that provides a mapping rule for each graph entity to be genereated from the source data. The following template shows what each rule in this object looks like:

{ "rules": [ { "rule_id": "(an identifier for this rule)", "rule_name": "(a name for this rule)", "table_name": "(the name of the table or view being loaded)", "vertex_definitions": [ { "vertex_id_template": "{col1}", "vertex_label": "(the vertex to create)", "vertex_definition_id": "(an identifier for this vertex)", "vertex_properties": [ { "property_name": "(name of the property)", "property_value_template": "{col2} or text", "property_value_type": "(data type of the property)" } ] } ] }, { "rule_id": "(an identifier for this rule)", "rule_name": "(a name for this rule)", "table_name": "(the name of the table or view being loaded)", "edge_definitions": [ { "from_vertex": { "vertex_id_template": "{col1}", "vertex_definition_id": "(an identifier for the vertex referenced above)" }, "to_vertex": { "vertex_id_template": "{col3}", "vertex_definition_id": "(an identifier for the vertex referenced above)" }, "edge_id_template": { "label": "(the edge label to add)", "template": "{col1}_{col3}" }, "edge_properties":[ { "property_name": "(the property to add)", "property_value_template": "{col4} or text", "property_value_type": "(data type like String, int, double)" } ] } ] } ] }

Note that the presence of a vertex label implies that the vertex is being created here, whereas its absence implies that the vertex is created by a different source, and this definition is only adding vertex properties.

Here is a sample rule for an employee record:

{ "rules": [ { "rule_id": "1", "rule_name": "vertex_mapping_rule_from_nodes", "table_name": "nodes", "vertex_definitions": [ { "vertex_id_template": "{emp_id}", "vertex_label": "employee", "vertex_definition_id": "1", "vertex_properties": [ { "property_name": "name", "property_value_template": "{emp_name}", "property_value_type": "String" } ] } ] }, { "rule_id": "2", "rule_name": "edge_mapping_rule_from_emp", "table_name": "nodes", "edge_definitions": [ { "from_vertex": { "vertex_id_template": "{emp_id}", "vertex_definition_id": "1" }, "to_vertex": { "vertex_id_template": "{mgr_id}", "vertex_definition_id": "1" }, "edge_id_template": { "label": "reportsTo", "template": "{emp_id}_{mgr_id}" }, "edge_properties":[ { "property_name": "team", "property_value_template": "{team}", "property_value_type": "String" } ] } ] } ] }