14.2.1.2.1 Graph-Bound Maps

Some data types like VERTEX or EDGE depend on the graph. Consequently, mappings involving these data types also depend on the graph. PGX provides PgxGraph and PgxMap APIs to manage such maps.

The following describes the usage of graph-bound maps.

You must first load the graph to work with vertex and edge maps.

You can create a graph-bound map using vertices as keys as shown in the following code:

• JShell
• Java
• Python

v0 = graph.getVertex(100)
v1 = graph.getVertex(101)
v2 = graph.getVertex(102)
v3 = graph.getVertex(103)

vertexToLongMap = graph.createMap(PropertyType.VERTEX, PropertyType.LONG, "vertexToLongMap")
vertexToLongMap.put(v0, v0.getDegreeAsync().get())
vertexToLongMap.put(v1, v1.getDegreeAsync().get())
vertexToLongMap.put(v2, v2.getDegreeAsync().get())
vertexToLongMap.put(v3, v3.getDegreeAsync().get())

import java.util.Arrays;
import oracle.pgx.api.*;
...
PgxVertex v0 = graph.getVertex(100);
PgxVertex v1 = graph.getVertex(101);
PgxVertex v2 = graph.getVertex(102);
PgxVertex v3 = graph.getVertex(103);

PgxMap<PgxVertex, Long> vertexToLongMap = graph.createMap(PropertyType.VERTEX, PropertyType.LONG, "vertexToLongMap");
vertexToLongMap.put(v0, v0.getDegree());
vertexToLongMap.put(v1, v1.getDegree());
vertexToLongMap.put(v2, v2.getDegree());
vertexToLongMap.put(v3, v3.getDegree());

v0 = graph.get_vertex(100)
v1 = graph.get_vertex(101)
v2 = graph.get_vertex(102)
v3 = graph.get_vertex(103)

vertex_to_long_map = graph.create_map("vertex", "long", "vertex_to_long_map")
vertex_to_long_map.put(v0, v0.degree)
vertex_to_long_map.put(v1, v1.degree)
vertex_to_long_map.put(v2, v2.degree)
vertex_to_long_map.put(v3, v3.degree)

You can create graph-bound maps using edges as keys as shown in the following code:

• JShell
• Java
• Python

e0 = graph.getEdge(100)
e1 = graph.getEdge(101)
e2 = graph.getEdge(102)
e3 = graph.getEdge(103)

edgeToVertexMap = graph.createMap(PropertyType.EDGE, PropertyType.VERTEX, "edgeToVertexMap")
edgeToVertexMap.put(e0, e0.getSource())
edgeToVertexMap.put(e1, e1.getSource())
edgeToVertexMap.put(e2, e2.getSource())
edgeToVertexMap.put(e3, e3.getSource())

import java.util.Arrays;
import oracle.pgx.api.*;
...
PgxEdge e0 = graph.getEdge(100);
PgxEdge e1 = graph.getEdge(101);
PgxEdge e2 = graph.getEdge(102);
PgxEdge e3 = graph.getEdge(103);

PgxMap<PgxEdge, PgxVertex> edgeToVertexMap = graph.createMap(PropertyType.EDGE, PropertyType.VERTEX, "edgeToVertexMap");
edgeToVertexMap.put(e0, e0.getSource());
edgeToVertexMap.put(e1, e1.getSource());
edgeToVertexMap.put(e2, e2.getSource());
edgeToVertexMap.put(e3, e3.getSource());

e0 = graph.get_edge(100) 
e1 = graph.get_edge(101) 
e2 = graph.get_edge(102) 
e3 = graph.get_edge(103)

edge_to_long_map = graph.create_map("edge", "long", "edge_to_long_map") 
edge_to_long_map.put(e0, e0.source) 
edge_to_long_map.put(e1, e1.source) 
edge_to_long_map.put(e2, e2.source) 
edge_to_long_map.put(e3, e3.source)

Note:

If you destroy the graph you will lose the map. Consider using a session-bound maps instead if your map does not involve any graph-related key or value type.