0017 External Identifiers¶
External identifiers are used to correlate the identifiers used in third party metadata catalogs with open metadata elements.
ExternalId¶
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 (how it is generated and managed) is stored in
keyPattern
. These are the values it can take, with the default (and most used) beingLOCAL_KEY
:Value Meaning 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.
ExternalIdLink¶
The mapping of identifiers can be many-to-many, which is why you see that the ExternalIdLink
relationship between the OpenMetadataRoot
(open metadata resources) and the ExternalId
is also many-to-many.
This relationship includes properties to help to map the OpenMetadataRoot
to the external identifier.
ExternalIdScope¶
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 Referenceable
that represents the third party metadata catalog. Typically, this is a type of SoftwareCapability
, for example, AssetManager
.
Further information
There is an article on managing external identifiers to correlate metadata elements from different types of technologies.