0017 External Identifiers
External Identifiers are used to correlate the identifiers used in third party metadata catalogs with open metadata elements. The ExternalId entity describes an external identifier from a specific third party metadata repository. It includes:
- The identifier value itself in identifier.
The pattern used for the identifier - in terms of how it is generated and managed is stored in keyPattern. These are the values it can take. The default (and most used) value is LOCAL_KEY.
- LOCAL_KEY - Unique key allocated and used within the scope of a single system.
- RECYCLED_KEY - Key allocated and used within the scope of a single system that is periodically reused for different records.
- NATURAL_KEY - Key derived from an attribute of the entity, such as email address, passport number.
- MIRROR_KEY - Key value copied from another system.
- AGGREGATE_KEY - Key formed by combining keys from multiple systems.
- CALLERS_KEY - Key from another system can bey used if system name provided.
- STABLE_KEY - Key value will remain active even if records are merged.
- OTHER - Another key pattern.
This mapping can be many-to-many which is why you see that the ExternalIdLink relationship between the open metadata element (resources) and the external identifier is also many-to-many.
This relationship includes properties to help to map the open metadata element to the external identifier.
There is no guarantee that external identifiers from a third party metadata catalog are globally unique and so the ExternalIdScope relationship links the external identifier to the open metadata element that represents the third party metadata catalog. Typically this is a type of SoftwareServerCapability, for example, AssetManager.
There is an article on the use of external identifiers for correlating metadata elements from different types of technologies here.
External identifiers are used extensively in the Asset Manager OMAS in order to correlate the identifiers from third party technologies and open metadata types.
External identifiers associated with an asset can be queried using the getAssetProperties() method from Asset Consumer OMAS and Asset Owner OMAS. It is also available through the getConnectedAssetProperties() method on connectors that have been created by Asset Consumer OMAS and Asset Owner OMAS.
License: CC BY 4.0, Copyright Contributors to the ODPi Egeria project.