Presentation by John Giles to Melbourne Scrum User group. From 26 Sept 2012

1. © 2012 Country Endeavours
“Creative Solutions for Difficult Problems”
The civil (uncivil?) war
-
Agilist vs. Data Architect
1. Understand the “enemy”
2. The mechanics of data pattern agility
3. Tips & techniques
4. Take-aways for you
(John Giles)
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2. © 2012 Country Endeavours
“Creative Solutions for Difficult Problems”
What’s the war really
about?
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3. Competing views
 Agilists
• Can’t wait for perfect design – miss the opportunity
• Don’t need perfection – achieve better via iterations
• Standards may reflect “old” – we can do better
• Hence opinion “We don’t need no … architects”
(Or at least the old-style ones)
 Architects
• “Integration” technical debt - Speedy delivery of
solutions = speedy delivery of integration problems
• Concern over “architecture breakers”
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4. Conflict resolution
(“fighting over the remote”)
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5. The vision for a creative win-win
 A start-up data architecture/model
• Based on proven patterns
• Assembled in days. Or even hours!
 Flexibility over successive iterations
• Start-up was minimal, but patterns extensible
 Simpler post-project integration (if required)
• If all enterprise data artifacts are built on common
patterns, integration-made-easy (almost)
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6. “Patterns” - elegance
today, flexibility tomorrow.
 Gamma et al: “Strict modeling of the real world leads
to a system that reflects today’s realities but not
necessarily tomorrow’s. The abstractions that emerge
during design are key to making a design flexible”
 Ambler: “Many agile developers underestimate the
value of data modeling and other data skills at their peril
… and have foregone opportunities for even greater
productivity and quality.”
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7. Modelling controversies
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8. I’ve been challenged!!!
 Three projects about to kick off
 All needed to be subsequently integrated, via
an enterprise data model (EDM)
 Competitor’s EDM took 5 years of effort
 My allowance – 10 days effort
 Solution: Len Silverston
• Len Silverston’s 50% to 75% theory
• Time-boxed interviews
• YAGNI (75% fit OK)
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9. © 2012 Country Endeavours
“Creative Solutions for Difficult Problems”
Mechanics of patterns
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10. Fine-grained “Elementary patterns”
Person skill acquisition SkillType
name skillTypeCode
dateOfBirth 0..* 0..* skillTypeDescription
Person personal skill record skill inventory 1 SkillType
name skillTypeCode
dateOfBirth 1 0..* 0..* skillTypeDescription
PersonalSkill
dateAcquired
Country Endeavours levelOfProficiency
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11. Resources & their attributes
0..1 FourWheelDriveCabChasis
emergency communications
current fitting registrationNumber
fuelType WaterBomber
0..1 communications 0..1
numberSeats
registrationNumber
waterCapacity
0..1 1..2 2..2 airSpeed
SlipOnTank Radio
waterCapacity radioType
pumpDeliveryRate make
fuelType model
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12. Using the EAV Elementary pattern
subclassification
0..* 0..1 Note that components of this Assembly Pattern
are based on the Entity/Attribute/Value (EAV)
classification Elementary pattern (also known by several
ResourceType
other titles e.g. the "Name/Value pair" pattern).
resourceTypeCode
resourceTypeDescription 1 inheritance
0..* 0..*
participant type1 1
ResourceSpecification
participant type2 1
resourceSpecificationName Utitilty-EAV::AttributeSpecification
0..1
0..* isAbstract attributeName
0..*
1 datatype
1 containment
ResourceToResourceRelationshipType template containment
1 1
resourceToResourceRelationshipTypeCode
resourceToResourceRelationshipTypeDescription specification
participant1Role Utitilty-EAV::AllowableAttribute
participant2Role 0..* 0..* 0..*
localName
classification 1 minOccurs
1 participant1 0..1
Resource 0..* maxOccurs Utitilty-EAV::EnumerationItem
participant2 1 derivationExpression
unitOfMeasure
effectivePeriod
0..* 0..* 0..* resourceName
1 constraint
1
identification
1 enumeratedValue Utitilty-EAV::DiscreteEnumerationItem
ResourceToResourceRelationship
enumerationValue
effectivePeriod 0..* 0..*
containment
0..* Utitilty-EAV::RangeEnumerationItem
ResourceIdentifier Utitilty-EAV::AttributeValue
effectivePeriod minimumValue
specifiedValue
resourceIdentifierType 0..* maximumValue
resourceIdentifierValue minimumBreakRule
maximumBreakRule
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13. One medium-grained pattern
- the face of “Party”
Party
effectivePeriod
Person
name
gender
Organization
registrationNumber
registeredName
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14. Drill-down for “Party”
RoleType
roleTypeCode
roleTypeDescription
identification 1 Party fulfilment classification
effectivePeriod 0..* 0..* 1
0..* (link) 1
nameDisplayString 1
Address
Role
PartyIdentifier effectivePeriod
1 effectivePeriod
partyIdentifierType (link) addressDisplayString
partyIdentifierValue
effectivePeriod
0..* 0..*
Person Organization PostalAddress
gender AddressService postalDeliveryDescription
containment containment town
effectivePeriod
state
1 1 addressUsageType
1..* postcode
1..* PhysicalAddress country
flatIdentifier
PersonName
floorIdentifier
effectivePeriod OrganizationName Emailddress
containment propertyName
personNameType effectivePeriod locationDescription emailAddressString
salutation 0..* orgNameType streetNumber
familyName 1 orgName streetName
postNominal town PhoneNumber
PersonGivenName
state countryPrefix
givenName postcode areaPrefix
sequenceNumber country localNumber
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15. A palette of “Assembly patterns”
Account
Task
Agreement
Resource
/ Asset
Document
Product
Event
Party & Role
Location
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16. Coarse-grained “Integration patterns”
Account copy
filed
Task constrained as
by Agreement
Document
Resource
/ Asset participates in,
sited signatory to, ...
at
Product Event
Party &
Role Location 2
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17. Or mineral exploration/extraction
Account copy
filed
as
Task constrained
by Agreement
archived
at
used as basis Storable
Resource for analysis in
object /
/ Asset participates in,
generates analysis document
sited signatory to, ...
results held as
at
associated
with
Product Event
Party &
Role Location
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18. … what about emergency response?
(or your problem?)
Account
Task
Agreement
Resource
/ Asset
Document
Product
Event
Party & Role
Country Endeavours Location
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19. (a possible solution framework)
Account
assigned
to Task
Agreement
triggers
Document
Resource occurs
/ Asset at
sited
at
manages,
owns, ...
(or "is")
associated
with
Product Event
occurs
at
based at,
Party &
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now at, ...
Role Location
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20. © 2012 Country Endeavours
“Creative Solutions for Difficult Problems”
Tips-&-techniques for
using patterns
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21. “In general, generalise”
AgreementType
PartyType agreementTypeCode
agreementTypeDesc
partyTypeCode
partyTypeDesc RoleType
1
classification roleTypeCode classification
0..1 roleTypeDesc cross-reference
0..* 0..*
0..* 1 classification Agreement
Party agreementReference 0..*
1 fulfilment 0..*
0..*
involvement
Role
effectivePeriod 2..*
Person 0..*
name Mortgage
dateOfBirth
loanToValueRatio
Solicitor
licenseNumber
Organization
registrationNumber
registeredName RealEstateAgent
registrationNumber
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22. Use patterns beyond
their intended purpose
1 GoodsItem
itemIdentifier usage rule
aggregation rule itemDescription 1
0..*
AssemblySpecificationItem
quantityRequired
0..*
1 Party
partyIdentifier
aggregation rule partyName 1 shareholding recording
0..*
Shareholding
shareholdingPercent
0..*
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23. Tailored extensions become a
pattern fulfilment
Party
effectivePeriod 1
nameDisplayString 0..* ContactReason
contactReasonCode
Role contactReasonDescription
1 0..1
effectivePeriod
status 0..1
0..1
constraint
specific constraint
0..* 0..*
(link) generic constraint ContactRuleSet
0..* effectivePeriod
0..* ContactRuleFilter
0..1 effectivePeriod
includeOrExcludeIndicator
Address
initial step restriction on use
effectivePeriod
addressDisplayString
(link) TimeOfDay
1 timePeriod
0..* 0..*
subsequent step DayOfWeek
AddressService 1 0..1 dayRange
effectivePeriod
rule target contact point
addressUsageType 1 ContactRuleStep
CalendarPeriod
0..1
0..* dateRange
1
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24. YAGNI Model Variable Acronym Operand Operator Operand
(You ain’t Num. Number
20 5 BR
1
WB minus
2
"7"
gonna need it) 20 6 SJ H minus “35”
Head rail
Model
modelNumber
Fixed panel top modelName
Door top
containment
Fixed panel (glass)
Sliding door
1
panel (glass)
Fixed panel side
Door side
0..*
Side jamb
Towell bar Variable
variableNumber
variableAcronym
Door bottom
variableName
Fixed panel bottom
Bottom rail
Measurement Computation
operand1
operator
Country Endeavours operand2
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25. Take the enterprise view
(& challenge the concepts)
Party - Simplified
name
address
phone
Employee Customer
1 fulfilment effectivePeriod effectivePeriod
name name
address address
0..* phone phone
salary creditLimit
Role superannuationFund industryCode
effectivePeriod
EmployeeRole CustomerRole
salary creditLimit
superannuationFund industryCode
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26. The “T-model” approach
 Mile-wide, inch-deep (touch points at least)
 Drill-down only where required
 Iterate within project, & across projects
Account Agreement Document Party/Role (etc.)
High-level logical
subject areas     
Standard logical
assembly patterns  
Refined logical
assembly patterns 
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27. © 2012 Country Endeavours
“Creative Solutions for Difficult Problems”
Take-away notes for you
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28. Does it really work?
 Some real-life stories
• Weeks, not months, for a usable framework
 But
• It’s more of a framework than an implementation
design
• The 80/20 rule doesn’t work
 Even with “patterns”, there is a place for (agile)
modellers!!!
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29. Messages for modellers?
 The Agile world is different:
• Modelling “ain’t enough”
• Deliver early, stay to refine, integrate at end
 There’s a need to learn about:
• “Agile” (Scrum, Kanban, Lean, stand-ups, UX, …)
• Patterns, and their integration
• OO – More than reading UML
 It can be fun working with agilists
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30. Messages for agilists?
 Welcome (agile) modellers, & be patient
 Jointly identify/mitigate “architecture breakers”
 Help “data” types with solutions beyond patterns
 Tell “data” types your expectations:
• Want a framework in your first iteration (not
perfect, but it should be robust, extensible)
• They need to keep an eye on integration – it’s their job
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31. Conclusion?
 Start-up models?
 Flexibility over successive iterations?
 Simpler post-project integration ?
… and any questions?
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