EnterpriseGraphs Management

An EnterpriseGraph is a specialized version of a SmartGraph, which means that both modules work similarly. The major difference is that EnterpriseGraphs rely on a special automated sharding of the underlying collections and hence can only work with collections that are created through the EnterpriseGraph itself. EnterpriseGraphs cannot overlap.

To generally understand the concept of this module please read the chapter about General Graph Management first, and continue with SmartGraph Management.

Create a Graph

EnterpriseGraphs require edge relations to be created. The format of the relations is identical to the format used for General Graphs. The only difference is that all collections used within the relations to create a new EnterpriseGraph must not exist yet. You have to let the EnterpriseGraph module create the Graph collections for you, so that it can enforce the correct sharding.

graph_module._create(graphName, edgeDefinitions, orphanCollections, smartOptions)

• graphName (string): Unique identifier of the graph.
• edgeDefinitions (array): List of relation definition objects, may be empty.
• orphanCollections (array): List of additional vertex collection names, may be empty.
• smartOptions (object): A JSON object having the following keys:
  • numberOfShards (number): The number of shards that are created for each collection. To maintain the correct sharding, all collections need an identical number of shards. This cannot be modified after the creation of the graph.
  • isSmart (bool): Mandatory parameter that needs to be set to true to create an EnterpriseGraph.
  • satellites (array, optional): An array of collection names that is used to create SatelliteCollections for an EnterpriseGraph. Each array element must be a string and a valid collection name. The collection type cannot be modified later.

The creation of a graph requires the name and some SmartGraph options. Due to the API, edgeDefinitions and orphanCollections have to be given but both can be empty arrays and be added later.

The edgeDefinitions can be created using the convenience method _relation known from the general-graph module, which is also available here.

orphanCollections again is just a list of additional vertex collections which are not yet connected via edges but should follow the same sharding to be connected later on. Note that these collections are not necessarily orphans in the graph theoretic sense: it is possible to add edges having one end in a collection that has been declared as orphan.

All collections used within the creation process are newly created. The process fails if one of them already exists, unless they have the correct sharding already. All newly created collections are immediately dropped again in the failure case.

Examples

Create a graph without relations. Edge definitions can be added later:

var graph_module = require("@arangodb/enterprise-graph");
var graph = graph_module._create("myGraph", [], [], {isSmart: true, numberOfShards: 9});
graph;

{[EnterpriseGraph] 
}

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

var graph_module = require("@arangodb/enterprise-graph");
var edgeDefinitions = [ graph_module._relation("edges", "vertices", "vertices") ];
var graph = graph_module._create("myGraph", edgeDefinitions, [], {isSmart: true, numberOfShards: 9});
graph;

{[EnterpriseGraph] 
  "edges" : [ArangoCollection 6010187, "edges" (type edge, status loaded)], 
  "vertices" : [ArangoCollection 6010177, "vertices" (type document, status loaded)] 
}

Create a graph with edge definitions and orphan collections:

var graph_module = require("@arangodb/enterprise-graph");
var edgeDefinitions = [ graph_module._relation("myRelation", ["male", "female"], ["male", "female"]) ];
var graph = graph_module._create("myGraph", edgeDefinitions, ["sessions"], {isSmart: true, numberOfShards: 9});
graph;

{[EnterpriseGraph] 
  "myRelation" : [ArangoCollection 6010237, "myRelation" (type edge, status loaded)], 
  "female" : [ArangoCollection 6010236, "female" (type document, status loaded)], 
  "male" : [ArangoCollection 6010235, "male" (type document, status loaded)], 
  "sessions" : [ArangoCollection 6010225, "sessions" (type document, status loaded)] 
}

Modify a graph definition at runtime

After you have created an EnterpriseGraph, its definition is not immutable. You can still add or remove relations. This is again identical to General Graphs.

However, there is one important difference: you can only add collections that either do not exist, or that have been created by this graph earlier. The latter can be the case if you, for example, remove an orphan collection from this graph, without dropping the collection itself. When after some time you decide to add it to the graph again, you can do it. This is because the enforced sharding is still applied to this vertex collection.

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 is dropped if it is not used in any other graph. Default: false.

In most cases, this function works identically to the General Graph one. However, there is one special case: the first vertex collection added to the graph (either orphan or within a relation) defines the sharding for all collections within the graph. Every other collection has its distributeShardsLike attribute set to the name of the initial collection. This collection cannot be dropped as long as other collections follow its sharding (i.e. they need to be dropped first).

Examples

Create an EnterpriseGraph and list its orphan collections:

var graph_module = require("@arangodb/enterprise-graph");
var relation = graph_module._relation("edges", "vertices", "vertices");
var graph = graph_module._create("myGraph", [relation], ["other"], {isSmart: true, numberOfShards: 9});
graph._orphanCollections();

[ 
  "other" 
]

Remove the orphan collection from the EnterpriseGraph and drop the collection:

graph._removeVertexCollection("other", true);
graph = graph_module._graph("myGraph");

{[EnterpriseGraph] 
  "edges" : [ArangoCollection 6010370, "edges" (type edge, status loaded)], 
  "vertices" : [ArangoCollection 6010359, "vertices" (type document, status loaded)] 
}

Attempting to remove a non-orphan collection results in an error:

graph._removeVertexCollection("vertices"); 

[ArangoError 1928: collection is not in list of orphan collections]

You cannot drop the initial collection (vertices) as long as it defines the sharding for other collections (edges).

var graph_module = require("@arangodb/enterprise-graph");
var relation = graph_module._relation("edges", "vertices", "vertices");
var graph = graph_module._create("myGraph", [relation], [], {isSmart: true, numberOfShards: 9});
graph._deleteEdgeDefinition("edges");
graph._removeVertexCollection("vertices");
db._drop("vertices"); 

[ArangoError 1485: Collection 'vertices' must not be dropped while '_from_edges', '_to_edges', '_local_edges', 'edges' have distributeShardsLike set to 'vertices'.]

You may drop the complete graph including the underlying collections by setting the second argument in the call to _drop() to true. This only drops collections that are in the graph definition at that point. Remember to manually drop collections that you might have removed from the graph beforehand.

var graph_module = require("@arangodb/enterprise-graph");
var relation = graph_module._relation("edges", "vertices", "vertices");
var graph = graph_module._create("myGraph", [relation], [], {isSmart: true, numberOfShards: 9});
graph._deleteEdgeDefinition("edges");      // Remove edge collection from graph definition
graph._removeVertexCollection("vertices"); // Remove vertex collection from graph definition
graph_module._drop("myGraph", true);       // Does not drop any collections because none are left in the graph definition
db._drop("edges"); // Manually clean up the collections that were left behind, drop 'edges' before sharding-defining 'vertices' collection
db._drop("vertices");

Empty Output

Alternatively, you can truncate() all collections of the graph if you just want to get rid of the data but keep the collections and graph definition.

Remove an edge collection

Delete an edge definition from the graph:

graph._deleteEdgeDefinition(edgeCollectionName, dropCollection)

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

Examples

Create an EnterpriseGraph, then delete the edge definition and drop the edge collection:

var graph_module = require("@arangodb/enterprise-graph");
var relation = graph_module._relation("edges", "vertices", "vertices");
var graph = graph_module._create("myGraph", [relation], [], {isSmart: true, numberOfShards: 9});
graph._deleteEdgeDefinition("edges", true);
graph = graph_module._graph("myGraph");

{[EnterpriseGraph] 
  "vertices" : [ArangoCollection 6010559, "vertices" (type document, status loaded)] 
}

It is allowed to remove the vertex collection vertices if it is not used in any relation (i.e. after the deletion of the edge definition):

graph._deleteEdgeDefinition("edges");
graph._removeVertexCollection("vertices");

Empty Output

Keep in mind that you cannot drop the vertices collection until no other collection references it anymore (distributeShardsLike collection property).

Remove a Graph

Remove a SmartGraph:

graph_module._drop(graphName, dropCollections)

• graphName (string): Name of the Graph.
• dropCollections (bool, optional): Define if collections should be dropped. Default: false.

Examples

Delete an EnterpriseGraph and drop its collections:

graph_module._drop("myGraph", true);

Empty Output

Note that removing a Graph with the option to drop the collections fails if you removed collections from the Graph but did not drop these collections. This is because their distributeShardsLike attribute still references collections that are part of the Graph. Dropping collections while others point to them in this way is not allowed. Make sure to drop the referencing collections first.

graph._removeVertexCollection("other");
graph_module._drop("myGraph", true); 

[ArangoError 1485: Collection 'vertices' must not be dropped while 'other' has distributeShardsLike set to 'vertices'.]