arangodb/Documentation/Books/Manual/Graphs/GeneralGraphs

Graphs
======

This chapter describes the [general-graph](../README.md) module.
It allows you to define a graph that is spread across several edge and document collections.
This allows you to structure your models in line with your domain and group them logically in collections giving you the power to query them in the same graph queries.
There is no need to include the referenced collections within the query, this module will handle it for you.

#### Three Steps to create a graph

* Create a graph

    @startDocuBlockInline generalGraphCreateGraphHowTo1
    @EXAMPLE_ARANGOSH_OUTPUT{generalGraphCreateGraphHowTo1}
      var graph_module = require("@arangodb/general-graph");
      var graph = graph_module._create("myGraph");
      graph;
    ~ graph_module._drop("myGraph", true);
    @END_EXAMPLE_ARANGOSH_OUTPUT
    @endDocuBlock generalGraphCreateGraphHowTo1

* Add some vertex collections

    @startDocuBlockInline generalGraphCreateGraphHowTo2
    @EXAMPLE_ARANGOSH_OUTPUT{generalGraphCreateGraphHowTo2}
    ~ var graph_module = require("@arangodb/general-graph");
    ~ var graph = graph_module._create("myGraph");
      graph._addVertexCollection("shop");
      graph._addVertexCollection("customer");
      graph._addVertexCollection("pet");
      graph;
    ~ graph_module._drop("myGraph", true);
    @END_EXAMPLE_ARANGOSH_OUTPUT
    @endDocuBlock generalGraphCreateGraphHowTo2

* Define relations on the Graph

    @startDocuBlockInline generalGraphCreateGraphHowTo3
    @EXAMPLE_ARANGOSH_OUTPUT{generalGraphCreateGraphHowTo3}
    ~ var graph_module = require("@arangodb/general-graph");
    ~ var graph = graph_module._create("myGraph");
    ~ graph._addVertexCollection("pet");
      var rel = graph_module._relation("isCustomer", ["shop"], ["customer"]);
      graph._extendEdgeDefinitions(rel);
      graph;
    ~ graph_module._drop("myGraph", true);
    @END_EXAMPLE_ARANGOSH_OUTPUT
    @endDocuBlock generalGraphCreateGraphHowTo3