There is support for the System Database and System Indexing features. The purpose of the System Database is to allow you
to run queries against your entire
Niagara system (
Supervisor and those stations connected to it). This allows your searches and hierarchies to span the entire system.
The System Database (SystemDb) is where a
Supervisor station stores indexed entities. It is responsible for adding, removing, and querying entities to/from a backend database.
The SystemDb only supports NEQL queries run against it.
Entities in
Niagara are basically composed of an ORD (Object Resolution Descriptor) identifier, tags and relations. For details on tags and relations,
see the Niagara Tagging Guide and Niagara Relations Guide.All components (including networks, devices, and points) satisfy this definition of an entity, while histories, alarms and
other types of files do not. Additionally, entities are the basis of NEQL queries which are used by the Hierarchy and Search
services.
JACE stations will not have a System Database, but their information may be indexed and placed in the
Supervisor’s System Database. The
Supervisor station is the only station that can access the SystemDb. Once entities are stored in the SystemDb, they can be queried by
services, for example HierarchyService and SearchService, and other processes.
NOTE: The SystemDb is currently intended to run only on
Supervisor platforms, not on JACE platforms. The System Indexing operations may only affect JACEs if exporting the index data to the
Supervisor instead of using the more common import or global import of index data, both of which are configured on the
Supervisor side.
When the
Supervisor queries the SystemDb for information about subordinate stations (via NEQL), the resulting entities are resolved in the form
of
Niagara virtuals, since they already allow for configuring user permissions on virtual components in the
Supervisor.