Practical Domain-Driven Design Modeling Exercise NDC Oslo 2025 Mufrid Krilic, Domain-Driven Design Coach CoWork, Norway 

What is the problem we are trying to solve? 

We all do modeling…. We have no choice! A model is an abstraction of reality where we choose to keep the most relevant elements • The challenge is to be as explicit as possible about modeling • “the most relevant elements” 

What will we cover in next 2 hours? 

What can you expect to learn in next 2 hours? Get encouraged to practice modeling (even more) in your context Do not settle at the first model! 

Storytelling with Models «All Models are Wrong but Some are Useful» - George Box 

How does a model look like? • Conceptual model used for: • Product architecture • Domain model • System decomposition • User Journeys • Modeling language used for: • IT architecture • Code • User interface 

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Agenda When What 1020 About Modeling  You are Here Part 1 Modeling by Functions/Tasks 15 minutes Exercise/Skill Builder Part 2 Modeling by Roles 15 minutes Exercise/Skill Builder Learn from each other – visit other groups 1120-1140 Break What happened in real-life story? Part 3 Modeling by Roles and Time 15 minutes Exercise/Skill Builder Part 4 Modeling by Capabilities 15 minutes Exercise/Skill Builder Learn from each other – visit other groups 1230 What happened in real-life story? Wrap-up 

The real-life story…. The backdrop for the exercise 

▪ For patients with identical diagnoses sometimes the treatment has the best effect when done in a group of patients ▪ Examples: • Conversation therapy groups in psychiatry • Training sessions post-injury Domain: Healthcare - Group Therapy 

Your role today: Product team! • Model a product/system that can help your client support group therapy in a better way than with the existing system • Client: • Head of a moderate-size hospital in Norway • 14000 employees • 1 million patient appointments per year 

What is the current status at our hospital? • Legacy patient record system in production for many years • Group therapy functionality • Many manual routines added to “keep the system afloat” 

▪ Group Therapy: Setting up a group • Planning ▪ Group Therapy: Conducting group appointments • Check-in process Domain use-cases 

Group Therapy Planning Somatic Department Rehabilitation after lifestyle affected diagnosis 

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Wait a minute! • Didn’t we just model something? • Yes! • Proving that modeling can be done in many ways 

domainstorytelling.org domainstorytelling.org 

Different kinds of models • Model of the existing socio- technical process for the group therapy As-Is • We want a new model for improved product/system support To-Be This was “As-Is” domain story This is the goal for today! 

Modeling by Functions/Tasks Exercise 1 

Functional Decomposition • Boundaries in the system follow the function that a user needs to do hers/his job • Classic approach • Boundary = Function 

Model a product/system for Group Therapy thus far • Build a model based on functions/tasks in the domain story • Example of a function/task: Sending a letter to patient • Be clear about boundaries in the product/system • Model boundaries around functions 

Agenda When What 1020 About Modeling Part 1 Modeling by Functions/Tasks 15 minutes Exercise/Skill Builder Part 2 Modeling by Roles  You are Here 15 minutes Exercise/Skill Builder Learn from each other – visit other groups 1120-1140 Break What happened in real-life story? Part 3 Modeling by Roles and Time 15 minutes Exercise/Skill Builder Learn from each other – visit other groups Part 4 Modeling by Capabilities 15 minutes Exercise/Skill Builder 1230 What happened in real-life story? Wrap-up 

▪ Group Therapy: Setting up a group • Planning ▪ Group Therapy: Conducting group appointments • Check-in process Domain use-cases 

Group Therapy Check-In Somatic Department Rehabilitation after lifestyle affected diagnosis 

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Modeling by Roles Exercise 2 

Role-based decomposition • Boundaries in the system based on which roles perform different functions • Leads to more task-oriented model • Boundary = Role based function 

Model a product/system for Group Therapy thus far • Build a model based on roles in the domain story • Example of a role: human and system actors • Be clear about boundaries in the product/system • Model boundaries around which roles perform different functions 

Learn from each other! Visit other groups and exchange modeling approaches 

Break 20 minutes! Product Development Coaching 

Agenda When What 1020 About Modeling Part 1 Modeling by Functions/Tasks 15 minutes Exercise/Skill Builder Part 2 Modeling by Roles 15 minutes Exercise/Skill Builder Learn from each other – visit other groups 1120-1140 Break What happened in real-life story?  You are Here Part 3 Modeling by Roles and Time 15 minutes Exercise/Skill Builder Learn from each other – visit other groups Part 4 Modeling by Capabilities 15 minutes Exercise/Skill Builder 1230 What happened in real-life story? Wrap-up 

Review Exercise 1 and 2 What happened in real-life story? 

Group Therapy Functions 

Domain Model 

Model of a “Group” • “Group” is defined as a set of properties needed to perform all the functions 

Definition of a “Group” model • Physician and specialists • Patients • Appointments • Location/Venue • Patient attendance, including no-show • Patients exempted from payment • Invoice – preferred method • Diagnosis-based patient fee • Reference to § in law for compulsory interventions in psychiatry 

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Who is the user? 

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Role-based model “Group” planning context • Specialists • Patients • Appointments • Location • Reference to § in law for psychiatry “Group” check-in context • Patient attendance incl. no-show • Cancelled appointments • Patients exempted from payment • Invoice – preferred method • Diagnosis-based patient fee 

Modeling by Roles and Time Exercise 3 

Time- and role-based decomposition • Boundaries in the system based on which roles perform different function at different times • Supports context-oriented systems • Boundary = Role-based function in a user context 

Model a product/system for Group Therapy thus far • Build a model based on roles and time in the domain story • Can you model Time explicitly? • Hint: Can activity ordering in domain story help? • Be clear about boundaries in the product/system • Model boundaries around which roles perform different functions at different times 

Learn from each other! Visit other groups and exchange modeling approaches 

Review Exercise 3 What happened in real-life story? 

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Who is the user? 

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Time- and role-based model “Group” planning context • Specialists • Patients • Appointments • Location • Reference to § in law for psychiatry “Group” check-in context • Patients exempted from payment • Invoice preferred method • Diagnosis-based patient fee “Group” billing context • Patient attendance, incl. no-show • Cancelled appointments 

Agenda When What 1020 About Modeling Part 1 Modeling by Functions/Tasks 15 minutes Exercise/Skill Builder Part 2 Modeling by Roles 15 minutes Exercise/Skill Builder Learn from each other – visit other groups 1120-1140 Break What happened in real-life story? Part 3 Modeling by Roles and Time 15 minutes Exercise/Skill Builder Learn from each other – visit other groups Part 4 Modeling by Capabilities  You are Here 15 minutes Exercise/Skill Builder 1230 What happened in real-life story? Wrap-up 

Agenda When What 1050 About Modeling Part 1 Modeling by Functions/Tasks 15 minutes Exercise/Skill Builder Part 2 Modeling by Roles 15 minutes Exercise/Skill Builder Learn from each other – visit other groups 1150-1210 Break What happened in real-life story? Part 3 Modeling by Roles and Time 15 minutes Exercise/Skill Builder Part 4 Modeling by Capabilities  You are Here 15 minutes Exercise/Skill Builder Learn from each other – visit other groups 1300 What happened in real-life story? Wrap-up 

Group Therapy Planning Psychiatric Department Adult Psychiatry 

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Modeling by Capabilities Exercise 4 

Group Planning Somatic Department 

Group Planning Psychiatric Department 

Departments •Accident and Emergency Department •Anaesthesia and Surgical Services •Cancer Treatment and Medical Physics •Children and Youth Clinic •Clinical Nutrition •Communication •Department of Occupational Therapy •Dermatology •Emergency Clinic •Emergency Department Short Stay Unit •Finance •Haukeland hotel •Heart Disease •Human Resources •Internal Medicine •International Collaboration •Laboratory Medicine and Pathology •Maternity Ward •Medical Biochemistry and Pharmacology MBF •Medical Genetics •Neurology •Neurosurgery •Occupational Medicine •Occupational Outpatient Clinic •Ophthalmology •Oral Surgery •Orthopedic Clinic •Physiotherapy •Psychiatry •Radiology department •Recruitment and Temporary Staffing Office •Regional Centre for Asthma, Allergy and Other Hypersensitivity illnesses in Western Norway •Research and Development •Rheumatology •Secretariat for hospital management •Surgical Clinic •The Cancer Center for Education and rehabilitation- CCER •The Norwegian Arthritis Registry - NorArthritis •The Norwegian Porphyria Centre NAPOS •Thoracic Medicine •Treatment abroad •Tuberculosis clinic •Women's Clinic 

Decompositions by business capabilities • Boundaries in the system follow the capabilities that the business offers its’ customers • Boundary = Business Capability • Boundary ≠ Function • Model around the way the business is organized! 

Model a product/system for Group Therapy thus far • Build a model based on capabilities in the hospital • Hint: Look out for the differences in the working process • Hint: Look out how the hospital is organized • Be clear about boundaries in the product/system • Model boundaries around the purpose for the hospital 

Review Exercise 4 What happened in real-life story? 

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Model by Capabilities “Group” – psychiatry capability • Psychologist • Psychiatrist • Diagnosis • Reference to § in law • Patients • Appointments • Location for appointment outside hospital premises “Group” – medical clinical services • Physician • Diagnosis • Patients • Appointments 

Wrap-up Where to go from here? 

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Core Domain • The thing that distinguishes you from the competitors • “Not every part of the system will be well-designed” • Generic subdomain • Supporting subdomain 

Product Architecture Which users are we tailoring our products for? The cost of customizing the product for diverse user groups The cost of developing separate products for separate user groups 

Software Architecture Aligning system boundaries with business intent Re-usable generic domain model that can be adapted to serve needs of multiple user groups Specific domain model highly aligned with needs of specific user groups 

Do not settle at the first model! 

Practice! Start on Monday! Somewhere in safe environments then improve! 

Thank You! Get in touch for further study and more hints! • [email protected] Helping Build Domain-Driven Product Organizations 

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Images • Vecteezy.com • Tim Hüfner • https://unsplash.com/@joshua_hoehne • https://unsplash.com/@kattyukawa • https://unsplash.com/@brett_jordan