#6 in my series, Design of Digital Machines Describes what a data model is, visualization standards, and data modeling challenges.

1. Data Model
Who lives here?
№ 6, Design of Digital Machines
Tim Sheiner
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States.

2. The four sub models of the machine
object model
Input Controller
Output
View Model
Digital Machine
interaction model data model
conceptual model
The data model corresponds most closely to the model.
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 2

3. What is stored where?
The data model defines storage.
๏ what information is stored?
๏ how is the store organized?
Storage, in turn, defines inheritance
๏ how do I get from here to there?
๏ what attributes will I find when I get there?
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 3

4. Let’s begin to understand the
data model by starting with the
data
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 4

5. An example: backpacking stoves
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 5

6. Specifically, the old skool fav:
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 6

7. Data is details
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 7

8. Name:value pairs are a simple structure
item # 708999
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 8

9. Name:value pairs are a simple structure
name value
item # 708999
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 8

10. Name:value pairs are a simple structure
name value
item # 708999
brand MSR
model WhisperLite Shaker Jet
price $79.95
auto ignition no
weight 11 oz
average boil time 238 sec
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 8

11. Name:value pairs are a simple structure
name value
item # 708999
brand MSR
model WhisperLite Shaker Jet
price $79.95 object properties or attributes
auto ignition no
weight 11 oz
average boil time 238 sec
object
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 8

12. A group of name:value pairs is a vector
item # 708999
brand MSR
model WhisperLite Shaker Jet
price $79.95
auto ignition no
weight 11 oz
average boil time 238 sec
variables values
vector
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 9

13. Vectors can be written as an array
(item #, brand, model, price, auto ignition, weight, average boil time)
(708999, MSR, WhisperLite Shaker Jet, 79.95, no, 11, 238)
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 10

14. Vectors can be written as an array
(item #, brand, model, price, auto ignition, weight, average boil time) variables
(708999, MSR, WhisperLite Shaker Jet, 79.95, no, 11, 238)
values
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 10

15. Vectors can be written in matrix form
average boil
item # image brand model price ($) auto ignition weight (oz) time (sec)
WhisperLite
708999 MSR 79.95 no 11 238
Shaker Jet
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 11

16. A collection of vectors is matrix or a
table
average boil
item # image brand model price ($) auto ignition weight (oz) time (sec)
WhisperLite
708999 MSR 80 no 11 238
Shaker Jet
722001 MSR XGK EX 150 no 13 296
813622 Jetboil Sol 120 yes 11 300
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 12

17. More terminology
average boil
item # image brand model price ($) auto ignition weight (oz) time (sec)
WhisperLite
708999 MSR 80 no 11 238
Shaker Jet
722001 MSR XGK EX 150 no 13 296
813622 Jetboil Sol 120 yes 11 300
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 13

18. More terminology
columns (variables)
average boil
item # image brand model price ($) auto ignition weight (oz) time (sec)
WhisperLite
708999 MSR 80 no 11 238
Shaker Jet
rows 722001 MSR XGK EX 150 no 13 296
(values)
813622 Jetboil Sol 120 yes 11 300 a record
(a vector)
record ID
(must be unique)
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 13

19. More terminology
columns (variables)
average boil
item # image brand model price ($) auto ignition weight (oz) time (sec)
WhisperLite
708999 MSR 80 no 11 238
Shaker Jet
rows 722001 MSR XGK EX 150 no 13 296
(values)
813622 Jetboil Sol 120 yes 11 300 a record
(a vector)
record ID categorical
(must be unique)
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 13

20. More terminology
columns (variables)
average boil
item # image brand model price ($) auto ignition weight (oz) time (sec)
WhisperLite
708999 MSR 80 no 11 238
Shaker Jet
rows 722001 MSR XGK EX 150 no 13 296
(values)
813622 Jetboil Sol 120 yes 11 300 a record
(a vector)
record ID categorical continuous
(must be unique)
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 13

21. More terminology
columns (variables)
average boil
item # image brand model price ($) auto ignition weight (oz) time (sec)
WhisperLite
708999 MSR 80 no 11 238
Shaker Jet
rows 722001 MSR XGK EX 150 no 13 296
(values)
813622 Jetboil Sol 120 yes 11 300 a record
(a vector)
record ID categorical continuous
(must be unique) boolean
(special kind of category)
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 13

22. More terminology
columns (variables)
average boil
item # image brand model price ($) auto ignition weight (oz) time (sec)
WhisperLite
708999 MSR 80 no 11 238
Shaker Jet
rows 722001 MSR XGK EX 150 no 13 296
(values)
813622 Jetboil Sol 120 yes 11 300 a record
(a vector)
record ID categorical continuous
(must be unique) boolean
(special kind of category)
time
(special kind of continuous)
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 13

23. Statistics are not data
average boil
item # image brand model price ($) auto ignition weight (oz)
time (sec)
WhisperLite
708999 MSR 79.95 no 11 238
Shaker Jet
722001 MSR XGK EX 149.95 no 13.2 296
813622 Jetboil Sol 119.95 yes 10.5 300
Averages 116.62 11.6 278 data
statistic
When used as a presentation tool, tables often mix data and statistics.
Data are observations.
Statistics are methods of aggregating, compressing and transforming data.
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 14

24. Now we understand data.
What about the data model?
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 15

25. Data are the observations
weight EGK EX Pocket Rocket
image brand price ($) (oz)
MSR 80 11
MSR 150 13
$149.95 $39.95
13.2 oz 3 oz
Jetboil 120 11
WhisperLite Shaker Jet
MSR 40 3 Sol
$79.95
11 oz $119.95
10.5 oz
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 16

26. The data model is the organization
Camping & Hiking
data model Backpacking Stoves
Liquid Fuel Canister
Activity MSR MSR
EGK EX Pocket Rocket
Equipment Type
Equipment Subtype
Brand
$149.95 $39.95
Model 13.2 oz 3 oz
metadata Jetboil
WhisperLite Shaker Jet
Sol
$79.95
11 oz $119.95
10.5 oz
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 17

27. The data model is a point of view
about inheritance
descendent - Camping & Hiking parent-child relationship
Activity
- Backpacking Stoves
Equipment Type - Liquid Fuel Stoves
Equipment Subtype - MSR
Brand - WhisperLite Shaker Jet
siblings
Model - EGK EX
metadata
- Canister
ancestor - MSR
siblings - Pocket Rocket
- Jetboil
- Sol
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 18

28. The data model is a point of view
about inheritance
descendent - Camping & Hiking parent-child relationship
Activity
- Backpacking Stoves
Equipment Type - Liquid Fuel Stoves
Equipment Subtype - MSR
Brand - WhisperLite Shaker Jet
siblings
Model - EGK EX
metadata
- Canister
ancestor - MSR
siblings - Pocket Rocket
- Jetboil
- Sol
a point of view, not the point of view
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 18

29. The data model is an general inheritance
solution for all system objects
instance
model Camping & Hiking>Backpacking Stoves>Liquid Fuel Stoves>MSR>WhisperLite Shaker Jet
Activity
Equipment Type
Equipment Subtype instance
Kayaking & Canoeing>Canoes>Recreational Canoes>Mad River>Adventure 16
Brand
Model
instance
Climbing>Chalk>Chalk Bags>Prana>Eagle Eye
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 19

30. The data model is an general inheritance
solution for all system objects
instance
model Camping & Hiking>Backpacking Stoves>Liquid Fuel Stoves>MSR>WhisperLite Shaker Jet
Activity
Equipment Type
Equipment Subtype instance
Kayaking & Canoeing>Canoes>Recreational Canoes>Mad River>Adventure 16
Brand
Model
instance
Climbing>Chalk>Chalk Bags>Prana>Eagle Eye
a solution, not the solution
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 19

31. Communicating the Data Model
Several standard forms
๏ hierarchy
๏ set diagram
๏ illustration
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 20

32. Data Model Example
Hierarchy & Sets
This baroque example
includes a simple
hierarchy illustrating the
general case, and then a
modified set display to
demonstrate a specific
case.
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States.

33. Data Model Example
Illustration
An illustration can be
helpful to show
relationships between
sibling nodes in the
structure.
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States.

34. How do you design a data
model?
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 23

35. Data modeling challenges
๏ Controlled Vocabulary
a restricted list of names for the objects in the system
๏ Taxonomy
a hierarchical structure that defines the inheritance relationships in the system
๏ Metadata
the object attributes used to distinguish taxonomic siblings
๏ Information Architecture
the design of the vocabulary, taxonomy and metadata
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 24

36. Controlled vocabulary captures meaning
The Whorfian hypothesis is about the question of whether
words influence thought.
Data modeling is agnostic with respect to this question, but
deterministic on the point that words influence communication.
The controlled vocabulary should capture the terms used by
system experts to communicate precisely.
Edward Sapir/Benjamin Whorf
Different
words for
different
states of
rice
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 25

37. Taxonomy is arbitrary
Originally, taxonomy described a method for classifying
the natural world.
In the context of a data model, it is the rule set by which
objects are placed into a hierarchical structure based
upon a controlled vocabulary.
Regardless of how carefully and objectively these rules
are constructed, never doubt that they are by definition
arbitrary.
Carl Linnaeus
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 26

38. Metadata separates siblings
data model instance
Activity - Camping & Hiking
Equipment Type - Backpacking Stoves
Equipment Subtype - Liquid Fuel Stoves
Brand - MSR
Model - WhisperLite Shaker Jet
metadata - item #: 708999
- price: $79.95
- weight: 11oz
- EGK EX
- item #: 702201
- price: $149.95
- weight: 13oz
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 27

39. Information architecture is the art
Information architecture is the design of the data model
Data Storage System Navigation Information Display
Activity - Camping & Hiking
Equipment Type - Backpacking Stoves
Equipment Subtype - Liquid Fuel Stoves
Brand - MSR
Model - WhisperLite Shaker Jet
Information architecture’s concern is a data model that is functional across cases
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 28

40. fin
0.5beta 2013 This work by Tim Sheiner is licensed under a Creative Commons Attribution 3.0 United States. 29