ABSTRACT
Table 7.1 through Table 7.5 summarize the mathematical templates. Tree Templates https://www.niso.org/standards/z39-96/ns/oasis-exchange/table">
Template name
Synopsis
UML diagram
Use when
Frequency
Hardcoded tree
Specifies a type sequence, one for each level of the hierarchy.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg91_1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
The levels in a tree are known and ordered.
Seldom
Simple tree
Treats all nodes the same.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg91_2.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
A tree concerns only data structure.
Common
Structured tree
Differentiates leaf nodes from branch nodes.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg91_3.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
Branch nodes and leaf nodes differ.
Common
Overlapping tree
Permits a node to belong to multiple trees.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg91_4.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
A node can belong to more than one tree.
Occasional
Tree changing over time
Stores variants of a tree over time.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg91_5.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
There is history to record.
Occasional
Degenerate node and edge
Groups a parent with its children.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg91_6.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
There is data for the parent–child grouping.
Rare
Directed Graph Templates https://www.niso.org/standards/z39-96/ns/oasis-exchange/table">Template name
Synopsis
UML diagram
Use when
Frequency
Simple DG
Treats all nodes the same.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg92_1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
Edges are unimportant; nodes have the same kind of data. The DG is acyclic.
Occasional
Structured DG
Differentiates leaf nodes from branch nodes.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg92_2.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
Edges are unimportant; branch nodes and leaf nodes have different data. The DG is acyclic.
Occasional
Node–edge DG
Treats nodes and edges as peers.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg92_3.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
Nodes and edges can both have data; there can be multiple edges between a pair of nodes.
Common
Connection DG
Promotes a node–edge connection to an entity type.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg92_4.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
Connections have data.
Occasional
Simple DG changing over time
Stores variants of a DG over time.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg92_5.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
There is history to record; edges are unimportant. The DG is acyclic.
Seldom
Node–edge DG changing over time
Stores variants of a DG over time.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg92_6.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
There is history to record; edges are important.
Occasional
Undirected Graph Templates https://www.niso.org/standards/z39-96/ns/oasis-exchange/table">Template name
Synopsis
UML diagram
Use when
Frequency
Node–edge UDG
Treats nodes and edges as peers.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg93_1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
No edge connects to the same node.
Occasional
Connection UDG
Promotes a node–edge connection to an entity type.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg93_2.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
Connections have data or an edge connects to the same node.
Occasional
UDG changing over time
Stores variants of a UDG over time.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg93_3.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
There is history to record.
Seldom
Item Description Templates https://www.niso.org/standards/z39-96/ns/oasis-exchange/table">Template name
Synopsis
UML diagram
Use when
Frequency
Item description
Relates data and metadata in the same model.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg93_4.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
The same model relates data and metadata.
Frequent
Homomorphism
Expresses an analogy between two item description templates.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg93_5.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
Item description templates are involved in an analogy.
Occasional
Star Schema Template https://www.niso.org/standards/z39-96/ns/oasis-exchange/table">Template name
Synopsis
UML diagram
Use when
Frequency
Star schema
Represents data as facts that are bound to dimensions.
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315380131/c5dc4a5b-f512-4b6f-a253-face85c9263f/content/pg93_6.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
There must be a flexible structure for querying data.
Occasional (frequent for data warehouse)
