Graph Management

This chapter describes the javascript interface for creating and modifying named graphs.

Edge Definitions

An edge definition is always a directed relation of a graph. Each graph can have arbitrary many relations defined within the edge definitions array.

Initialize the List

Create a list of edge definitions to construct a graph:

graph_module._edgeDefinitions(relation1, relation2, ..., relationN)

• relation (object, optional): An object representing a definition of one relation in the graph

The list of edge definitions of a graph can be managed by the graph module itself. This function is the entry point for the management and will return the correct list.

Examples

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> directed_relation = graph_module._relation("lives_in", "user", "city");
arangosh> undirected_relation = graph_module._relation("knows", "user", "user");
arangosh> edgedefinitions = graph_module._edgeDefinitions(directed_relation, undirected_relation);

{ 
  "collection" : "lives_in", 
  "from" : [ 
    "user" 
  ], 
  "to" : [ 
    "city" 
  ] 
}
{ 
  "collection" : "knows", 
  "from" : [ 
    "user" 
  ], 
  "to" : [ 
    "user" 
  ] 
}
[ 
  { 
    "collection" : "lives_in", 
    "from" : [ 
      "user" 
    ], 
    "to" : [ 
      "city" 
    ] 
  }, 
  { 
    "collection" : "knows", 
    "from" : [ 
      "user" 
    ], 
    "to" : [ 
      "user" 
    ] 
  } 
]

Extend the List

Extend the list of edge definitions to construct a graph:

graph_module._extendEdgeDefinitions(edgeDefinitions, relation1, relation2, ..., relationN)

• edgeDefinitions (array): A list of relation definition objects.
• relationX (object): An object representing a definition of one relation in the graph

In order to add more edge definitions to the graph before creating this function can be used to add more definitions to the initial list.

Examples

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> directed_relation = graph_module._relation("lives_in", "user", "city");
arangosh> undirected_relation = graph_module._relation("knows", "user", "user");
arangosh> edgedefinitions = graph_module._edgeDefinitions(directed_relation);
arangosh> edgedefinitions = graph_module._extendEdgeDefinitions(undirected_relation);

{ 
  "collection" : "lives_in", 
  "from" : [ 
    "user" 
  ], 
  "to" : [ 
    "city" 
  ] 
}
{ 
  "collection" : "knows", 
  "from" : [ 
    "user" 
  ], 
  "to" : [ 
    "user" 
  ] 
}
[ 
  { 
    "collection" : "lives_in", 
    "from" : [ 
      "user" 
    ], 
    "to" : [ 
      "city" 
    ] 
  } 
]

Relation

Define a directed relation:

graph_module._relation(relationName, fromVertexCollections, toVertexCollections)

• relationName (string): The name of the edge collection where the edges should be stored. Will be created if it does not yet exist.
• fromVertexCollections (string|array): One or a list of collection names. Source vertices for the edges have to be stored in these collections. Collections will be created if they do not exist.
• toVertexCollections (string|array): One or a list of collection names. Target vertices for the edges have to be stored in these collections. Collections will be created if they do not exist.

The relationName defines the name of this relation and references to the underlying edge collection. The fromVertexCollections is an Array of document collections holding the start vertices. The toVertexCollections is an array of document collections holding the target vertices. Relations are only allowed in the direction from any collection in fromVertexCollections to any collection in toVertexCollections.

Examples

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> graph_module._relation("has_bought", ["Customer", "Company"], ["Groceries", "Electronics"]);

{ 
  "collection" : "has_bought", 
  "from" : [ 
    "Customer", 
    "Company" 
  ], 
  "to" : [ 
    "Groceries", 
    "Electronics" 
  ] 
}

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> graph_module._relation("has_bought", "Customer", "Product");

{ 
  "collection" : "has_bought", 
  "from" : [ 
    "Customer" 
  ], 
  "to" : [ 
    "Product" 
  ] 
}

Create a Graph

graph_module._create(graphName, edgeDefinitions, orphanCollections)

• graphName (string): Unique identifier of the graph
• edgeDefinitions (array, optional): List of relation definition objects
• orphanCollections (array, optional): List of additional vertex collection names

The creation of a graph requires the name of the graph and a definition of its edges.

For every type of edge definition a convenience method exists that can be used to create a graph. Optionally a list of vertex collections can be added, which are not used in any edge definition. These collections are referred to as orphan collections within this chapter. All collections used within the creation process are created if they do not exist.

Examples

Create an empty graph, edge definitions can be added at runtime:

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> graph = graph_module._create("myGraph");

{[Graph] 
}

Create a graph using an edge collection edges and a single vertex collection vertices:

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> var edgeDefinitions = [ { collection: "edges", "from": [ "vertices" ], "to" : [ "vertices" ] } ];
arangosh> graph = graph_module._create("myGraph", edgeDefinitions);

{[Graph] 
  "edges" : [ArangoCollection 72276, "edges" (type edge, status loaded)], 
  "vertices" : [ArangoCollection 72273, "vertices" (type document, status loaded)] 
}

Create a graph with edge definitions and orphan collections:

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> graph = graph_module._create("myGraph",
........> [graph_module._relation("myRelation", ["male", "female"], ["male", "female"])], ["sessions"]);

{[Graph] 
  "myRelation" : [ArangoCollection 72081, "myRelation" (type edge, status loaded)], 
  "female" : [ArangoCollection 72075, "female" (type document, status loaded)], 
  "male" : [ArangoCollection 72078, "male" (type document, status loaded)], 
  "sessions" : [ArangoCollection 72072, "sessions" (type document, status loaded)] 
}

Complete Example to Create a Graph

Example call:

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> var edgeDefinitions = graph_module._edgeDefinitions();
arangosh> graph_module._extendEdgeDefinitions(edgeDefinitions, graph_module._relation("friend_of", "Customer", "Customer"));
arangosh> graph_module._extendEdgeDefinitions(
........> edgeDefinitions, graph_module._relation(
........> "has_bought", ["Customer", "Company"], ["Groceries", "Electronics"]));
arangosh> graph_module._create("myStore", edgeDefinitions);

{[Graph] 
  "friend_of" : [ArangoCollection 77352, "friend_of" (type edge, status loaded)], 
  "Customer" : [ArangoCollection 77344, "Customer" (type document, status loaded)], 
  "has_bought" : [ArangoCollection 77347, "has_bought" (type edge, status loaded)], 
  "Company" : [ArangoCollection 77338, "Company" (type document, status loaded)], 
  "Electronics" : [ArangoCollection 77335, "Electronics" (type document, status loaded)], 
  "Groceries" : [ArangoCollection 77341, "Groceries" (type document, status loaded)] 
}

Alternative call:

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh>  var edgeDefinitions = graph_module._edgeDefinitions(
........>  graph_module._relation("friend_of", ["Customer"], ["Customer"]), graph_module._relation(
........> "has_bought", ["Customer", "Company"], ["Groceries", "Electronics"]));
arangosh> graph_module._create("myStore", edgeDefinitions);

{[Graph] 
  "friend_of" : [ArangoCollection 77394, "friend_of" (type edge, status loaded)], 
  "Customer" : [ArangoCollection 77386, "Customer" (type document, status loaded)], 
  "has_bought" : [ArangoCollection 77389, "has_bought" (type edge, status loaded)], 
  "Company" : [ArangoCollection 77380, "Company" (type document, status loaded)], 
  "Electronics" : [ArangoCollection 77377, "Electronics" (type document, status loaded)], 
  "Groceries" : [ArangoCollection 77383, "Groceries" (type document, status loaded)] 
}

List available Graphs

List all graphs:

graph_module._list()

Lists all graph names stored in this database.

Examples

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> graph_module._list();

[ ]

Load a Graph

Get a graph by its name:

graph_module._graph(graphName)

• graphName (string): Unique identifier of the graph

Examples

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> graph = graph_module._graph("social");

{[Graph] 
  "relation" : [ArangoCollection 72852, "relation" (type edge, status loaded)], 
  "female" : [ArangoCollection 72842, "female" (type document, status loaded)], 
  "male" : [ArangoCollection 72847, "male" (type document, status loaded)] 
}

Remove a Graph

Drop a Graph by its name:

graph_module._drop(graphName, dropCollections)

• graphName (string): Unique identifier of the graph
• dropCollections (bool, optional): Define if collections should be dropped (default: false)

This can drop all collections contained in the graph as long as they are not used within other graphs. To drop the collections only belonging to this graph, the optional parameter drop-collections has to be set to true.

Examples

Drop a graph and keep collections:

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> graph_module._drop("social");
arangosh> db._collection("female");
arangosh> db._collection("male");
arangosh> db._collection("relation");

[ArangoCollection 72359, "female" (type document, status loaded)]
[ArangoCollection 72364, "male" (type document, status loaded)]
[ArangoCollection 72369, "relation" (type edge, status loaded)]

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> graph_module._drop("social", true);
arangosh> db._collection("female");
arangosh> db._collection("male");
arangosh> db._collection("relation");

null
null
null

Modify a Graph definition at runtime

After you have created an graph its definition is not immutable. You can still add, delete or modify edge definitions and vertex collections.

Extend the Edge Definitions

Add another edge definition to the graph:

graph._extendEdgeDefinitions(edgeDefinition)

• edgeDefinition (object): The relation definition to extend the graph

Extends the edge definitions of a graph. If an orphan collection is used in this edge definition, it will be removed from the orphanage. If the edge collection of the edge definition to add is already used in the graph or used in a different graph with different from and/or to collections an error is thrown.

Examples

arangosh> var graph_module = require("@arangodb/general-graph")
arangosh> var ed1 = graph_module._relation("myEC1", ["myVC1"], ["myVC2"]);
arangosh> var ed2 = graph_module._relation("myEC2", ["myVC1"], ["myVC3"]);
arangosh> var graph = graph_module._create("myGraph", [ed1]);
arangosh> graph._extendEdgeDefinitions(ed2);

(Empty output)

Modify an Edge Definition

Modify a relation definition:

graph_module._editEdgeDefinitions(edgeDefinition)

• edgeDefinition (object): The edge definition to replace the existing edge definition with the same attribute collection.

Edits one relation definition of a graph. The edge definition used as argument will replace the existing edge definition of the graph which has the same collection. Vertex Collections of the replaced edge definition that are not used in the new definition will transform to an orphan. Orphans that are used in this new edge definition will be deleted from the list of orphans. Other graphs with the same edge definition will be modified, too.

Examples

arangosh> var graph_module = require("@arangodb/general-graph")
arangosh> var original = graph_module._relation("myEC1", ["myVC1"], ["myVC2"]);
arangosh> var modified = graph_module._relation("myEC1", ["myVC2"], ["myVC3"]);
arangosh> var graph = graph_module._create("myGraph", [original]);
arangosh> graph._editEdgeDefinitions(modified);

(Empty output)

Delete an Edge Definition

Delete one relation definition:

graph_module._deleteEdgeDefinition(edgeCollectionName, dropCollection)

• edgeCollectionName (string): Name of edge collection in the relation definition.
• dropCollection (bool, optional): Define if the edge collection should be dropped. Default: false

Deletes a relation definition defined by the edge collection of a graph. If the collections defined in the edge definition (collection, from, to) are not used in another edge definition of the graph, they will be moved to the orphanage.

Examples

Remove an edge definition but keep the edge collection:

arangosh> var graph_module = require("@arangodb/general-graph")
arangosh> var ed1 = graph_module._relation("myEC1", ["myVC1"], ["myVC2"]);
arangosh> var ed2 = graph_module._relation("myEC2", ["myVC1"], ["myVC3"]);
arangosh> var graph = graph_module._create("myGraph", [ed1, ed2]);
arangosh> graph._deleteEdgeDefinition("myEC1");
arangosh> db._collection("myEC1");

[ArangoCollection 76971, "myEC1" (type edge, status loaded)]

Remove an edge definition and drop the edge collection:

arangosh> var graph_module = require("@arangodb/general-graph")
arangosh> var ed1 = graph_module._relation("myEC1", ["myVC1"], ["myVC2"]);
arangosh> var ed2 = graph_module._relation("myEC2", ["myVC1"], ["myVC3"]);
arangosh> var graph = graph_module._create("myGraph", [ed1, ed2]);
arangosh> graph._deleteEdgeDefinition("myEC1", true);
arangosh> db._collection("myEC1");

null

Extend Vertex Collections

Each graph can have an arbitrary amount of vertex collections, which are not part of any edge definition of the graph. These collections are called orphan collections. If the graph is extended with an edge definition using one of the orphans, it will be removed from the set of orphan collection automatically.

Add a Vertex Collection

Add a vertex collection to the graph:

graph._addVertexCollection(vertexCollectionName, createCollection)

• vertexCollectionName (string): Name of vertex collection.
• createCollection (bool, optional): If true the collection will be created if it does not exist. Default: true

Adds a vertex collection to the set of orphan collections of the graph. If the collection does not exist, it will be created. If it is already used by any edge definition of the graph, an error will be thrown.

Examples

arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> var ed1 = graph_module._relation("myEC1", ["myVC1"], ["myVC2"]);
arangosh> var graph = graph_module._create("myGraph", [ed1]);
arangosh> graph._addVertexCollection("myVC3", true);

(Empty output)

Get the Orphaned Collections

Get all orphan collections:

graph._orphanCollections()

Returns all vertex collections of the graph that are not used in any edge definition.

Examples

arangosh> var graph_module = require("@arangodb/general-graph")
arangosh> var ed1 = graph_module._relation("myEC1", ["myVC1"], ["myVC2"]);
arangosh> var graph = graph_module._create("myGraph", [ed1]);
arangosh> graph._addVertexCollection("myVC3", true);
arangosh> graph._orphanCollections();

[ 
  "myVC3" 
]

Remove a Vertex Collection

Remove a vertex collection from the graph:

graph._removeVertexCollection(vertexCollectionName, dropCollection)

• vertexCollectionName (string): Name of vertex collection.
• dropCollection (bool, optional): If true the collection will be dropped if it is not used in any other graph. Default: false

Removes a vertex collection from the graph. Only collections not used in any relation definition can be removed. Optionally the collection can be deleted, if it is not used in any other graph.

Examples

arangosh> var graph_module = require("@arangodb/general-graph")
arangosh> var ed1 = graph_module._relation("myEC1", ["myVC1"], ["myVC2"]);
arangosh> var graph = graph_module._create("myGraph", [ed1]);
arangosh> graph._addVertexCollection("myVC3", true);
arangosh> graph._addVertexCollection("myVC4", true);
arangosh> graph._orphanCollections();
arangosh> graph._removeVertexCollection("myVC3");
arangosh> graph._orphanCollections();

[ 
  "myVC3", 
  "myVC4" 
]
[ 
  "myVC4" 
]

Manipulating Vertices

Save a Vertex

Create a new vertex in vertexCollectionName:

graph.vertexCollectionName.save(data)

• data (object): JSON data of vertex.

Examples

arangosh> var examples = require("@arangodb/graph-examples/example-graph.js");
arangosh> var graph = examples.loadGraph("social");
arangosh> graph.male.save({name: "Floyd", _key: "floyd"});

{ 
  "_id" : "male/floyd", 
  "_key" : "floyd", 
  "_rev" : "_fw2Y2lm--B" 
}

Replace a Vertex

Replaces the data of a vertex in collection vertexCollectionName:

graph.vertexCollectionName.replace(vertexId, data, options)

• vertexId (string): _id attribute of the vertex
• data (object): JSON data of vertex.
• options (object, optional): See collection documentation

Examples

arangosh> var examples = require("@arangodb/graph-examples/example-graph.js");
arangosh> var graph = examples.loadGraph("social");
arangosh> graph.male.save({neym: "Jon", _key: "john"});
arangosh> graph.male.replace("male/john", {name: "John"});

{ 
  "_id" : "male/john", 
  "_key" : "john", 
  "_rev" : "_fw2Y2lO--F" 
}
{ 
  "_id" : "male/john", 
  "_key" : "john", 
  "_rev" : "_fw2Y2lS---", 
  "_oldRev" : "_fw2Y2lO--F" 
}

Update a Vertex

Updates the data of a vertex in collection vertexCollectionName

graph.vertexCollectionName.update(vertexId, data, options)

• vertexId (string): _id attribute of the vertex
• data (object): JSON data of vertex.
• options (object, optional): See collection documentation

Examples

arangosh> var examples = require("@arangodb/graph-examples/example-graph.js");
arangosh> var graph = examples.loadGraph("social");
arangosh> graph.female.save({name: "Lynda", _key: "linda"});
arangosh> graph.female.update("female/linda", {name: "Linda", _key: "linda"});

{ 
  "_id" : "female/linda", 
  "_key" : "linda", 
  "_rev" : "_fw2Y2l6--D" 
}
{ 
  "_id" : "female/linda", 
  "_key" : "linda", 
  "_rev" : "_fw2Y2l6--E", 
  "_oldRev" : "_fw2Y2l6--D" 
}

Remove a Vertex

Removes a vertex in collection vertexCollectionName

graph.vertexCollectionName.remove(vertexId, options)

• vertexId (string): _id attribute of the vertex
• options (object, optional): See collection documentation

Additionally removes all ingoing and outgoing edges of the vertex recursively (see edge remove).

Examples

arangosh> var examples = require("@arangodb/graph-examples/example-graph.js");
arangosh> var graph = examples.loadGraph("social");
arangosh> graph.male.save({name: "Kermit", _key: "kermit"});
arangosh> db._exists("male/kermit")
arangosh> graph.male.remove("male/kermit")
arangosh> db._exists("male/kermit")

{ 
  "_id" : "male/kermit", 
  "_key" : "kermit", 
  "_rev" : "_fw2Y2k2--C" 
}
true
true
false

Manipulating Edges

Save a new Edge

Creates an edge from vertex data._from to vertex data._to in collection edgeCollectionName.

graph.edgeCollectionName.save(data, options)

• data (object): JSON data of the edge. Needs to include a _from attribute with the document identifier of the source vertex and a _to attribute with the document identifier of the target vertex.
• options (object, optional): See collection.save() options

Examples

arangosh> var examples = require("@arangodb/graph-examples/example-graph.js");
arangosh> var graph = examples.loadGraph("social");
arangosh> graph.relation.save({
........>   _from: "male/bob",
........>   _to: "female/alice",
........> _key: "bobAndAlice", type: "married" });

{ 
  "_id" : "relation/bobAndAlice", 
  "_key" : "bobAndAlice", 
  "_rev" : "_fw2Y2Lu---" 
}

If the collections of from and to are not defined in an edge definition of the graph, the edge will not be stored.

arangosh> var examples = require("@arangodb/graph-examples/example-graph.js");
arangosh> var graph = examples.loadGraph("social");
arangosh> graph.relation.save(
........>  "relation/aliceAndBob",
........>   "female/alice",
........> {type: "married", _key: "bobAndAlice"});

[ArangoError 1906: invalid edge between relation/aliceAndBob and female/alice. Doesn't conform to any edge definition]

Replace an Edge

Replaces the data of an edge in collection edgeCollectionName. Note that _from and _to are mandatory.

graph.edgeCollectionName.replace(edgeId, data, options)

• edgeId (string): _id attribute of the edge
• data (object, optional): JSON data of the edge
• options (object, optional): See collection documentation

Examples

arangosh> var examples = require("@arangodb/graph-examples/example-graph.js");
arangosh> var graph = examples.loadGraph("social");
arangosh> graph.relation.save("female/alice", "female/diana", {typo: "nose", _key: "aliceAndDiana"});
arangosh> graph.relation.replace("relation/aliceAndDiana", {type: "knows", _from: "female/alice", _to: "female/diana"});

{ 
  "_id" : "relation/aliceAndDiana", 
  "_key" : "aliceAndDiana", 
  "_rev" : "_fw2Y2LW--_" 
}
{ 
  "_id" : "relation/aliceAndDiana", 
  "_key" : "aliceAndDiana", 
  "_rev" : "_fw2Y2LW--A", 
  "_oldRev" : "_fw2Y2LW--_" 
}

Update an Edge

Updates the data of an edge in collection edgeCollectionName

graph.edgeCollectionName.update(edgeId, data, options)

• edgeId (string): _id attribute of the edge
• data (object, optional): JSON data of the edge
• options (object, optional): See collection documentation

Examples

arangosh> var examples = require("@arangodb/graph-examples/example-graph.js");
arangosh> var graph = examples.loadGraph("social");
arangosh> graph.relation.save("female/alice", "female/diana", {type: "knows", _key: "aliceAndDiana"});
arangosh> graph.relation.update("relation/aliceAndDiana", {type: "quarreled", _key: "aliceAndDiana"});

{ 
  "_id" : "relation/aliceAndDiana", 
  "_key" : "aliceAndDiana", 
  "_rev" : "_fw2Y2MW--B" 
}
{ 
  "_id" : "relation/aliceAndDiana", 
  "_key" : "aliceAndDiana", 
  "_rev" : "_fw2Y2MW--C", 
  "_oldRev" : "_fw2Y2MW--B" 
}

Remove an Edge

Removes an edge in collection edgeCollectionName

graph.edgeCollectionName.remove(edgeId, options)

• edgeId (string): _id attribute of the edge
• options (object, optional): See collection documentation

If this edge is used as a vertex by another edge, the other edge will be removed (recursively).

Examples

arangosh> var examples = require("@arangodb/graph-examples/example-graph.js");
arangosh> var graph = examples.loadGraph("social");
arangosh> graph.relation.save("female/alice", "female/diana", {_key: "aliceAndDiana"});
arangosh> db._exists("relation/aliceAndDiana")
arangosh> graph.relation.remove("relation/aliceAndDiana")
arangosh> db._exists("relation/aliceAndDiana")

{ 
  "_id" : "relation/aliceAndDiana", 
  "_key" : "aliceAndDiana", 
  "_rev" : "_fw2Y2K6--C" 
}
true
true
false