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 returns the correct list.
Examples
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
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. It is created if it does not exist yet.fromVertexCollections
(string|array): One or a list of collection names. Source vertices for the edges have to be stored in these collections. Collections are 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 are 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
A relation from one vertex collection to another:
A relation from multiple vertex collections to multiple others:
Edge Definition Options
The following edge definition options are supported:
satellites
(array, optional): An array of collection names that is used to create SatelliteCollections for a (Disjoint) SmartGraph using SatelliteCollections (Enterprise Edition only). Each array element must be a string and a valid collection name. The collection type cannot be modified later.
Create a Graph
graph_module._create(graphName, edgeDefinitions, orphanCollections)
graphName
(string): Unique identifier of the graphedgeDefinitions
(array, optional): List of relation definition objectsorphanCollections
(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");
{[GeneralGraph] }
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);
{[GeneralGraph]
"edges" : [ArangoCollection 75129, "edges" (type edge, status loaded)],
"vertices" : [ArangoCollection 75126, "vertices" (type document, status loaded)]
}
Create a graph with edge definitions and orphan collections:
Complete Example to Create a Graph
Example call:
Alternative call:
List available Graphs
Lists all graph names stored in this database:
graph_module._list()
Lists all graph definitions stored in this database:
graph_module._listObjects()
Examples
List the graph names:
arangosh> var graph_module = require("@arangodb/general-graph");
arangosh> graph_module._list();
[
"myGraph",
"myStore"
]
List the graph definitions:
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");
{[GeneralGraph]
"relation" : [ArangoCollection 75831, "relation" (type edge, status loaded)],
"female" : [ArangoCollection 75821, "female" (type document, status loaded)],
"male" : [ArangoCollection 75826, "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 graphdropCollections
(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 75212, "female" (type document, status loaded)]
[ArangoCollection 75217, "male" (type document, status loaded)]
[ArangoCollection 75222, "relation" (type edge, status loaded)]
Drop a graph and its collections:
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 a 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, options)
edgeDefinition
(object): The relation definition to extend the graphoptions
(object): Additional options related to the edge definition itself. See Edge Definition Options.
Extends the edge definitions of a graph. If an orphan collection is used in this
edge definition, it is 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
Modify an Edge Definition
Modify a relation definition:
graph_module._editEdgeDefinitions(edgeDefinition, options)
edgeDefinition
(object): The edge definition to replace the existing edge definition with the same attributecollection
.options
(object): Additional options related to the edge definition itself. See Edge Definition Options.
Edits one relation definition of a graph. The edge definition used as argument replaces 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 are transformed to an orphan. Orphans that are used in this new edge definition are deleted from the list of orphans. Other graphs with the same edge definition are 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);
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 are 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 79994, "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 is removed from the set of orphan collection automatically.
Add a Vertex Collection
Add a vertex collection to the graph:
graph._addVertexCollection(vertexCollectionName, createCollection, options)
vertexCollectionName
(string): Name of vertex collection.createCollection
(bool, optional): Iftrue
, the collection is created if it does not exist. Default:true
options
(object, optional): Additional options related to the edge definition itself. See Edge Definition Options.
Adds a vertex collection to the set of orphan collections of the graph. If the collection does not exist, it is created. If it is already used by any edge definition of the graph, an error is thrown.
Examples
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): Iftrue
, the collection is 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
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" : "_fyvNI2u--_"
}
Replace a Vertex
Replaces the data of a vertex in collection vertexCollectionName
:
graph.vertexCollectionName.replace(vertexId, data, options)
vertexId
(string):_id
attribute of the vertexdata
(object): JSON data of vertex.options
(object, optional): See collection documentation
Examples
Update a Vertex
Updates the data of a vertex in collection vertexCollectionName
.
graph.vertexCollectionName.update(vertexId, data, options)
vertexId
(string):_id
attribute of the vertexdata
(object): JSON data of vertex.options
(object, optional): See collection documentation
Examples
Remove a Vertex
Removes a vertex in collection vertexCollectionName
.
graph.vertexCollectionName.remove(vertexId, options)
vertexId
(string):_id
attribute of the vertexoptions
(object, optional): See collection documentation
Additionally removes all ingoing and outgoing edges of the vertex recursively (see edge remove).
Examples
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): Seecollection.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" : "_fyvNICu---"
}
If the collections of from
and to
are not defined in an edge definition
of the graph, the edge is not 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 edgedata
(object, optional): JSON data of the edgeoptions
(object, optional): See collection documentation
Examples
Update an Edge
Updates the data of an edge in collection edgeCollectionName
.
graph.edgeCollectionName.update(edgeId, data, options)
edgeId
(string):_id
attribute of the edgedata
(object, optional): JSON data of the edgeoptions
(object, optional): See collection documentation
Examples
Remove an Edge
Removes an edge in collection edgeCollectionName
.
graph.edgeCollectionName.remove(edgeId, options)
edgeId
(string):_id
attribute of the edgeoptions
(object, optional): See collection documentation
If this edge is used as a vertex by another edge, the other edge is removed (recursively).
Examples