A machine ID, or MID, is a globally unique identifier generated and used by a knowledge graph. In a knowledge graph, every entity has its own MID even though the entities come from different sources. A master entity with a new MID is created after reconciling and merging entities from multiple places. In this way, a knowledge graph tracks the data origin for every data point.
Cloud Knowledge Graph MID
Google Cloud Knowledge Graph introduces a new format of MID, c-024dcv3mk. A single-character namespace c is followed by a hyphen and the base-32 representation of an auto-generated alphanumeric ID. This new form of MID without / provides an easier way for modern applications to integrate. In Enterprise Knowledge Graph, there are two types of MIDs:
| Namespace | Example | Use |
|---|---|---|
c |
c-024dcv3mk |
Cloud Knowledge Graph MID |
r |
r-02b72jsgrbws18 |
Candidate MID generated from Entity Reconciliation Job |
e |
e-02b72jsgrbws18 |
Reconciled master entity MID in private graph |
Crossover to Google Knowledge Graph MID
The Google Knowledge Graph is a large knowledge base containing facts about people, places, books, and other kinds of entities. Some examples of Google Knowledge Graph entities include:
/m/0dl567— Taylor Swift/m/045c7b— Google
Cloud Knowledge Graph connects existing Google KG MIDs with the new Cloud KG MIDs. If you are already using /m or /g MIDs, you can continue to look up the entities. However, the return entity uses Cloud KG MID as a primary identifier, and Google Knowledge Graph MID is referenced in the identifier section.