If you are using ArangoDB databases as NoSQL data stores that are registered with your ArcGIS Knowledge site, there are details to consider to ensure that the knowledge graphs operate correctly.
Create a knowledge graph
The first step when using an ArangoDB database with an ArcGIS Knowledge site is to create an ArangoDB database using one of the tools provided for administering ArangoDB databases. The name you use for the database is subject to the same naming restrictions as the knowledge graph.
Register the database with your site as a NoSQL data store. When you provide authentication information to connect to the ArangoDB database, ensure that the user or identity with which the database is accessed has sufficient privileges to support all operations necessary to the knowledge graph.
The knowledge graph associated with the NoSQL data store will have the level of access associated with the credentials that were used to create the NoSQL data store. Those credentials are respected when any client accesses the knowledge graph service's content. For example, if the user can only access a specific set of entities and relationships, only those items will be available in an ArcGIS Pro project's investigation.
When you create a knowledge graph using a NoSQL data store, you must determine how the data stored in the ArangoDB database will be managed. In ArcGIS Enterprise 11.2, only ArcGIS-managed data can be stored in an ArangoDB database.
The graph store associated with your ArcGIS Knowledge site stores schema information that must be kept in sync with the information stored in the ArangoDB databases associated with your site. You must create a plan to back up and restore your ArangoDB databases that is coordinated with your plan to back up and restore your ArcGIS Enterprise deployment and your ArcGIS Data Store graph store.
When a knowledge graph will contain ArcGIS-managed data, the registered database must be empty when you add it to your ArcGIS Enterprise deployment as a NoSQL data store. If an ArangoDB database isn't empty, the operation to create a knowledge graph with ArcGIS-managed data will fail.
When you create a NoSQL data store that will contain ArcGIS-managed data, the credentials you provide to access the ArangoDB database must have the Administrate access level.
You can only create one NoSQL data store that accesses an ArangoDB database, and only one knowledge graph can be created that accesses the NoSQL data store.
Once a knowledge graph with ArcGIS-managed data has been created, the identifiers for entities and relationships must be kept in sync between the ArangoDB databases and the ArcGIS Knowledge graph store for the knowledge graph to remain operational. To ensure data integrity, edits to all systems associated with a knowledge graph, including associated ArangoDB databases, are only supported through operations and requests made to the knowledge graph in ArcGIS Pro and ArcGIS Enterprise.
Editing data and other changes to the ArangoDB database must not be made from outside ArcGIS. This includes changing or deleting any indexes associated with the ArangoDB database, since these are required to support searching.
Delete the database
When you no longer need a knowledge graph, you can delete it in the Enterprise portal. Data for the knowledge graph is deleted automatically from the graph store. However, if the knowledge graph references a NoSQL data store, the data store and its associated ArangoDB database are not deleted automatically.
If the knowledge graph contained ArcGIS-managed data, you can't create another ArcGIS-managed knowledge graph from the same NoSQL data store because the ArangoDB database is not empty.
You can delete the NoSQL data store in the Enterprise portal. This does not delete the associated ArangoDB database. Before you delete the NoSQL data store item, review its settings and note which ArangoDB database it references. You can take steps to archive the data and delete the ArangoDB database using ArangoDB tools according to your organization's guidelines.
Once a knowledge graph has been deleted from the Enterprise portal, you can't use any investigations stored in your ArcGIS Pro projects that referenced the deleted knowledge graph. An existing investigation can't be associated with a different knowledge graph. You must delete investigations that reference the deleted knowledge graph from all projects in which they exist or delete the projects, as appropriate.
If the knowledge graph has been transferred to a new Enterprise deployment, existing knowledge graph layers in a map or a link chart can be updated to use the new knowledge graph, even though the investigation must be deleted.