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https://issues.apache.org/jira/browse/ATLAS-1690?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15967319#comment-15967319
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Stefhan van Helvoirt commented on ATLAS-1690:
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Hi David,
Good to see a document specifically focussing on the relationships. Here by my
input, interested to hearing your response.
Page 1:
• “Metadata stores store metadata” re-write this to “Metadata repository
stores metadata” as it is less confusing.
• Suggestion to replace ‘metadata entity’ with ‘metadata object’, as the
term object is more generic.
• “Relationships include when Glossary Terms are linked to each other,
assets mapped to Glossary Terms and asset metadata linked together.” Are there
types of relationships between metadata objects that are excluded from this
scope?
Page 2:
• “As a 1 When this document refers to Glossary Term – it is referring to
those described in Jira 1410. Page 2 of 9 Glossary Term is linked to an asset,
we need to be aware that there are 3 owners, one for the Glossary Term one for
the asset and one for the relationship. This document proposes a design that
allows relationships to be considered in this way.” Does this state that we
consider relationships as ‘first class citizens’? As such that the relationship
between two objects becomes an object on its own, with a unique identifier and
potentially additional metadata?
• “When this document refers to Glossary Term – it is referring to those
described in Jira 1410.” This exact sentence was already mentioned as footnote
on page 1.
Page 5:
- “Relationship constraints can have an attribute name and a reverse
attribute name, but there is no label for the relationship itself – the
relationship name.” What about synonym relationships? What would then be the
attribute name and the reverse attribute name?
- With regards to the Bidirectional relationships example. It would be:
‘A person has a home address’/’A home address is of a person’. The ‘has a’ /
‘is of’ are two directional relationships that would always need to be kept in
sync. ‘A home address is a address’. A more accurate example of a bidirectional
relationship would be ‘First name is synonym of Given name’ / ‘Given name is
synonym of First name’
- With regards of the styles of relationships, perhaps its good idea to
adopt the terminology of:
o Hierarchical relationships (inheritance)
o Equivalence relationships (synonyms/is a)
o Associative relationships (related to / loosely coupled)
https://twobenches.wordpress.com/2008/06/04/semantic-relationships-in-a-thesaurus/
For inspiration see: Morville, Peter and Rosenfeld, Louis (2002)
http://yunus.hacettepe.edu.tr/~tonta/courses/fall2010/bby607/IAWWW.pdf
Page number 203, page 225, Definition ‘thesaurus’: A controlled vocabulary in
which equivalence, hierarchical, and associative relationships are identified
for purposes of improved retrieval.*
* Guidelines for the Construction, Format, and Management of Monolingual
Thesauri. ANSI/NISO Z39.19–1993 (R1998).
See also Figure 9-12. Semantic relationships in a thesaurus (Page number 204,
page 226).
See also Semantic Relationships (page number 215, page 237)
Page 7:
- Delete functionality. This is crucial as it will allow to cope with
changes in the metadata objects, and relationships provided by other metadata
repositories (e.g. other atlas instances).
- With regards to the discussion point on endpoints. Endpoints should not
be updated / modified when working on relationships. The relationship should
point to the object and subject identifier without impacting those objects in
any way. A separate mechanism should be responsible for interpreting the
relationships and if needed adjusting/updating the associated objects. E.g.
collapsing the assigned classification into the subject or one of the endpoints
of the subject (e.g. assigned information view).
Page 9:
- On ‘1 to 1 relationships’: I do not understand why this would be an
issue, if you would define the relationship object independently of the
endpoints. In that way, both endpoints need to exist (otherwise, you will not
even be able to select them) before you can create the relationship. Only the
relationship object will then be created pointing to the identifiers of both
the subject and object.
> Introduce top level relationships
> ---------------------------------
>
> Key: ATLAS-1690
> URL: https://issues.apache.org/jira/browse/ATLAS-1690
> Project: Atlas
> Issue Type: Improvement
> Reporter: David Radley
> Assignee: David Radley
> Labels: VirtualDataConnector
> Attachments: Atlas Relationships proposal v1.0.pdf
>
>
> Introduce top level relationships including support for
> -many to many relationships
> - relationship names including the name for both ends and the relationship.
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