Domain-driven design is a collaborative process involving both domain experts and software practitioners that attempts to address issues of complexity in software. This process is described in the book Domain-Driven Design written by Eric Evans. Domain-driven design starts with the assertion that complexity is in the domain, not in the technology. Accordingly, we must let technology play a supporting role.
A person practicing domain-driven design does not attempt to model reality. Instead, domain experts and software practitioners use a mental model as a tool for solving problems within a given domain. The domain experts and software practitioners collaborate to explore and develop this model. We will look at the concept of a bounded context within which models can be isolated and explored. We will talk about domain-driven design's building block patterns including entities, value objects, aggregates, repositories, services, and domain events. We will see how test-driven development can be used as a means of exploring the model.
Explain Domain-Driven Design, its main concepts and tools, and the Event Storming practice to highlight the importance of a good design and empower a team to start using it progressively.
Patterns and Anti-patterns
How to learn design patterns?
Categories of GoF patterns
The Fundamental theorem of software engineering
Real-world problems and how design patterns solve them with GoF structural patterns
4 pillars of visualization & communication by Noah Iliinskyiliinsky
A version of my standard "how to do visualization" talk from summer 2016. This version points out that the same process works for most modes of communication as well.
Explain Domain-Driven Design, its main concepts and tools, and the Event Storming practice to highlight the importance of a good design and empower a team to start using it progressively.
Patterns and Anti-patterns
How to learn design patterns?
Categories of GoF patterns
The Fundamental theorem of software engineering
Real-world problems and how design patterns solve them with GoF structural patterns
4 pillars of visualization & communication by Noah Iliinskyiliinsky
A version of my standard "how to do visualization" talk from summer 2016. This version points out that the same process works for most modes of communication as well.
Domain-driven design is a collaborative process involving both domain experts and software practitioners that attempts to address issues of complexity in software. This process is described in the book Domain-Driven Design (Addison-Wesley 2004) written by Eric Evans. Domain-driven design starts with the assertion that (for almost all software) complexity is in the domain, not in the technology. Accordingly, we must let technology play a supporting role. Domain-driven design attempts to focus on and distill the core domain for a given project.
Philosopher and scientist Alfred Korzybski said, "The map is not the territory." As such, a person practicing domain-driven design does not attempt to model reality. Instead, domain experts and software practitioners use a mental model as a tool for solving problems within a given domain. The domain experts and software practitioners collaborate to explore and develop this model. No software of any reasonable scope has just one model. We will look at the concept of a bounded context within which each model can be isolated and explored. Within a bounded context, collaborators must speak a ubiquitous language in order to reason about and discuss the model.
We will also talk about domain-driven design's building block patterns including entities, value objects, aggregates, repositories, services, and domain events. We will look at domain-driven design practices including supple design, strategic design, and distillation of the core. We will see how test-driven development can be used as a means of exploring the model. Examples in PHP will be provided of the building block patterns as well as other techniques including closure of operations, intention revealing interfaces, side-effect free functions, and assertions.
Domain Driven Design main concepts
This presentation is a summary of the book "Domain Driven Design" from InfoQ.
Here is the link: http://www.infoq.com/minibooks/domain-driven-design-quickly
Domain-driven design is a collaborative process involving both domain experts and software practitioners. This high-level overview takes a look at the driving principles behind domain-driven design. It also explores domain-driven design's building block patterns, supple design, strategic design, and distillation of the core.
This workshop focuses on domain driven design and how to achieve it effectively. It also focus on bridging gaps while gathering requirements from business stakeholders using event storming workshops.
A Practical Guide to Domain Driven Design: Presentation Slidesthinkddd
Tonight I presented on Domain Driven Design to the Alt.Net group in Sydney at the invite of Richard Banks.
As a follow up, attached are the slides I used, feel free to distribute and use on the Creative Commons Licence
В рамках C/C++/Embedded місяця у GlobalLogic нещодавно відбувся Online TechTalk "Patterns in Embedded SW Design"
Спікер розібрав паттерни на кісточки: від поняття до практичного використання з прикладом проєктного коду.
У доповіді спеціаліст розглянув:
- Поняття патернів у програмному забезпеченні з акцентом на Embedded розробку.
- Основні переваги використання патернів.
- Класифікацію патернів для Embedded напрямку, деякі з них було розглянуто.
- Було наведено приклад використання на прикладі проєктного коду.
Деталі та відео заходу: https://bit.ly/3DaKx7t
One of the main advantages of PHP is that it allows you and your company to build up projects in no time and with immediate feedback and business value. Sometimes, however, fast growth and unprevented complexities could make your codebase more and more difficult to manage as time passes and new features are added.Domain Driven Design can be an elegant solution to the problem, but introducing it in mid-large sized projects is not always easy: you have to deal with difficulties at technical, team and knowledge levels. This talk focuses on how to approach the change in your codebase and in your team mindset without breaking legacy code or stopping the development in favor of neverending refactoring sessions.
Based on my observations, in IT we suffer from continuous collective amnesia and we are even proud of it.
For at least 50 years meanwhile, we struggle how to build systems, that are easy to understand, to maintain, to change and to operate in a reliable way. Each time we hit the wall again, we start to look for a new silver bullet on the horizon, strongly believing that it will solve the problem for good.
The key word is "new": "New" is good in our community, while "old" is bad, worthless, crap. We suffer from youthism, not only in recruiting, but in all areas. This way we discard any "old" knowledge, no matter if it is valuable or not. We separate by age, not by value.
Additionally we continuously lose our collective memory with every new generation that leaves university as they are also taught not to value anything old and instead only look for the new, shiny stuff.
While not all old knowledge is worth being preserved, admittedly, there is still a lot of valuable old knowledge available, offering answers to the problems that we face today - creating maintainable and reliable systems, dealing with distribution and tackling complexity, just to name a few of the challenges.
This presentation is a journey through some (very) old computer science papers that contain a lot of very valuable knowledge regarding the problems we face today. For each of the papers, some of the key ideas are presented and how they address our current challenges.
Of course, the voice track is missing and there are a lot more papers that would be worth being mentioned in this presentation. Still, I hope that also the slides alone will be of some value for you - and convince you a bit that not everything "old" in IT is automatically worthless ... ;)
Entity Relationships in a Document Database at CouchConf BostonBradley Holt
Unlike relational databases, document databases like CouchDB and Couchbase do not directly support entity relationships. This talk will explore patterns of modeling one-to-many and many-to-many entity relationships in a document database. These patterns include using an embedded JSON array, relating documents using identifiers, using a list of keys, and using relationship documents.
In this talk we'll see how to build CouchApps using CouchDB, Javascript, and HTML5. We'll look at related tools such as the couchapp command ine tool, the Evently jQuery plugin, the CouchDB API jQuery plugin, the CouchApp Loader, Pathbinder, and the Mustache templating framework.
Domain-driven design is a collaborative process involving both domain experts and software practitioners that attempts to address issues of complexity in software. This process is described in the book Domain-Driven Design (Addison-Wesley 2004) written by Eric Evans. Domain-driven design starts with the assertion that (for almost all software) complexity is in the domain, not in the technology. Accordingly, we must let technology play a supporting role. Domain-driven design attempts to focus on and distill the core domain for a given project.
Philosopher and scientist Alfred Korzybski said, "The map is not the territory." As such, a person practicing domain-driven design does not attempt to model reality. Instead, domain experts and software practitioners use a mental model as a tool for solving problems within a given domain. The domain experts and software practitioners collaborate to explore and develop this model. No software of any reasonable scope has just one model. We will look at the concept of a bounded context within which each model can be isolated and explored. Within a bounded context, collaborators must speak a ubiquitous language in order to reason about and discuss the model.
We will also talk about domain-driven design's building block patterns including entities, value objects, aggregates, repositories, services, and domain events. We will look at domain-driven design practices including supple design, strategic design, and distillation of the core. We will see how test-driven development can be used as a means of exploring the model. Examples in PHP will be provided of the building block patterns as well as other techniques including closure of operations, intention revealing interfaces, side-effect free functions, and assertions.
Domain Driven Design main concepts
This presentation is a summary of the book "Domain Driven Design" from InfoQ.
Here is the link: http://www.infoq.com/minibooks/domain-driven-design-quickly
Domain-driven design is a collaborative process involving both domain experts and software practitioners. This high-level overview takes a look at the driving principles behind domain-driven design. It also explores domain-driven design's building block patterns, supple design, strategic design, and distillation of the core.
This workshop focuses on domain driven design and how to achieve it effectively. It also focus on bridging gaps while gathering requirements from business stakeholders using event storming workshops.
A Practical Guide to Domain Driven Design: Presentation Slidesthinkddd
Tonight I presented on Domain Driven Design to the Alt.Net group in Sydney at the invite of Richard Banks.
As a follow up, attached are the slides I used, feel free to distribute and use on the Creative Commons Licence
В рамках C/C++/Embedded місяця у GlobalLogic нещодавно відбувся Online TechTalk "Patterns in Embedded SW Design"
Спікер розібрав паттерни на кісточки: від поняття до практичного використання з прикладом проєктного коду.
У доповіді спеціаліст розглянув:
- Поняття патернів у програмному забезпеченні з акцентом на Embedded розробку.
- Основні переваги використання патернів.
- Класифікацію патернів для Embedded напрямку, деякі з них було розглянуто.
- Було наведено приклад використання на прикладі проєктного коду.
Деталі та відео заходу: https://bit.ly/3DaKx7t
One of the main advantages of PHP is that it allows you and your company to build up projects in no time and with immediate feedback and business value. Sometimes, however, fast growth and unprevented complexities could make your codebase more and more difficult to manage as time passes and new features are added.Domain Driven Design can be an elegant solution to the problem, but introducing it in mid-large sized projects is not always easy: you have to deal with difficulties at technical, team and knowledge levels. This talk focuses on how to approach the change in your codebase and in your team mindset without breaking legacy code or stopping the development in favor of neverending refactoring sessions.
Based on my observations, in IT we suffer from continuous collective amnesia and we are even proud of it.
For at least 50 years meanwhile, we struggle how to build systems, that are easy to understand, to maintain, to change and to operate in a reliable way. Each time we hit the wall again, we start to look for a new silver bullet on the horizon, strongly believing that it will solve the problem for good.
The key word is "new": "New" is good in our community, while "old" is bad, worthless, crap. We suffer from youthism, not only in recruiting, but in all areas. This way we discard any "old" knowledge, no matter if it is valuable or not. We separate by age, not by value.
Additionally we continuously lose our collective memory with every new generation that leaves university as they are also taught not to value anything old and instead only look for the new, shiny stuff.
While not all old knowledge is worth being preserved, admittedly, there is still a lot of valuable old knowledge available, offering answers to the problems that we face today - creating maintainable and reliable systems, dealing with distribution and tackling complexity, just to name a few of the challenges.
This presentation is a journey through some (very) old computer science papers that contain a lot of very valuable knowledge regarding the problems we face today. For each of the papers, some of the key ideas are presented and how they address our current challenges.
Of course, the voice track is missing and there are a lot more papers that would be worth being mentioned in this presentation. Still, I hope that also the slides alone will be of some value for you - and convince you a bit that not everything "old" in IT is automatically worthless ... ;)
Entity Relationships in a Document Database at CouchConf BostonBradley Holt
Unlike relational databases, document databases like CouchDB and Couchbase do not directly support entity relationships. This talk will explore patterns of modeling one-to-many and many-to-many entity relationships in a document database. These patterns include using an embedded JSON array, relating documents using identifiers, using a list of keys, and using relationship documents.
In this talk we'll see how to build CouchApps using CouchDB, Javascript, and HTML5. We'll look at related tools such as the couchapp command ine tool, the Evently jQuery plugin, the CouchDB API jQuery plugin, the CouchApp Loader, Pathbinder, and the Mustache templating framework.
CouchDB is a document-oriented database that uses JSON documents, has a RESTful HTTP API, and is queried using map/reduce views. Each of these properties alone, especially MapReduce views, may seem foreign to developers more familiar with relational databases. This tutorial will teach web developers the concepts they need to get started using CouchDB in their projects. Several CouchDB libraries are available for PHP and we will take a look at the more popular ones.
jQuery Conference Boston 2011 CouchAppsBradley Holt
CouchApps are web applications built using CouchDB, JavaScript, and HTML5. CouchDB is a document-oriented database that stores JSON documents, has a RESTful HTTP API, and is queried using MapReduce views. This talk will answer your fundamental questions about CouchDB and will cover the basics of building CouchApps using jQuery and various jQuery plugins.
CouchApps are web applications built using CouchDB, JavaScript, and HTML5. CouchDB is a document-oriented database that stores JSON documents, has a RESTful HTTP API, and is queried using map/reduce views. This talk will answer your basic questions about CouchDB, but will focus on building CouchApps and related tools.
CouchDB is a document-oriented database that uses JSON documents, has a RESTful HTTP API, and is queried using map/reduce views. Each of these properties alone, especially MapReduce views, may seem foreign to developers more familiar with relational databases. This tutorial will teach web developers the concepts they need to get started using CouchDB in their projects. CouchDB’s RESTful HTTP API makes it suitable for interfacing with any programming language. CouchDB libraries are available for many programming languages and we will take a look at some of the more popular ones.
This is a presentation made at the Burlington, Vermont PHP Users Group about configuring load balancing using the Apache HTTP Server. Load balancing is a technique that can distribute work across multiple server nodes—here we will discuss load balancing HTTP (i.e. web) traffic. There are many software and hardware load balancing options available including HAProxy, Varnish, Pound, Perlbal, Squid, nginx, and Linux-HA (High-Availability Linux) on Linux Standard Base (LSB). However, many web developers are already familiar with Apache as a web server and it is relatively easy to also configure Apache as a load balancer.
Related concepts such as shared nothing architecture are discussed. We also take a look at some basic load balancing scenarios and features including sticky sessions and proxying requests based on HTTP method. Distributed load testing with Tsung is briefly discussed as well.
This is a presentation on CouchDB that I gave at the New York PHP User Group. I talked about the basics of CouchDB, its JSON documents, its RESTful API, writing and querying MapReduce views, using CouchDB from within PHP, and scaling.
This is a "PHP 201" presentation that was given at the December 2010 Burlington, Vermont PHP Users group meeting. Going beyond the basics, this presentation covered working with arrays, functions, and objects.
PHP 5.3 was released in 2009 and is the newest version of PHP. Bradley Holt will talk about the new features available including namespaces, closures (lamdba/anonymous functions), and late static binding. Learn how these new features might be useful to you and why the next major version of the big PHP frameworks will require PHP 5.3.
This presentation will discuss how the Representational State Transfer (REST) architectural style can be applied to the design of your web services.
You will learn how to use HTTP methods and status codes properly and we will discuss how to use Hypermedia As The Engine Of Application State (HATEOAS). The principles of REST and HATEOAS will be demonstrated through the Atom Publishing Protocol (AtomPub) using the Google Data APIs and other AtomPub implementations as examples.
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
Leonard Jayamohan, Partner & Generative AI Lead, Deloitte
This keynote will reveal how Deloitte leverages Neo4j’s graph power for groundbreaking digital twin solutions, achieving a staggering 100x performance boost. Discover the essential role knowledge graphs play in successful generative AI implementations. Plus, get an exclusive look at an innovative Neo4j + Generative AI solution Deloitte is developing in-house.
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
Maruthi Prithivirajan, Head of ASEAN & IN Solution Architecture, Neo4j
Get an inside look at the latest Neo4j innovations that enable relationship-driven intelligence at scale. Learn more about the newest cloud integrations and product enhancements that make Neo4j an essential choice for developers building apps with interconnected data and generative AI.
In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
We will explore the capabilities of AI in understanding XML markup languages and autonomously creating structured XML content. Additionally, we will examine the capacity of AI to enrich plain text with appropriate XML markup. Practical examples and methodological guidelines will be provided to elucidate how AI can be effectively prompted to interpret and generate accurate XML markup.
Further emphasis will be placed on the role of AI in developing XSLT, or schemas such as XSD and Schematron. We will address the techniques and strategies adopted to create prompts for generating code, explaining code, or refactoring the code, and the results achieved.
The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
By highlighting the potential advantages and challenges of integrating AI with XML development tools and languages, the presentation seeks to inspire thoughtful conversation around the future of XML development. We’ll not only delve into the technical aspects of AI-powered XML development but also discuss practical implications and possible future directions.
Threats to mobile devices are more prevalent and increasing in scope and complexity. Users of mobile devices desire to take full advantage of the features
available on those devices, but many of the features provide convenience and capability but sacrifice security. This best practices guide outlines steps the users can take to better protect personal devices and information.
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
Communications Mining Series - Zero to Hero - Session 1DianaGray10
This session provides introduction to UiPath Communication Mining, importance and platform overview. You will acquire a good understand of the phases in Communication Mining as we go over the platform with you. Topics covered:
• Communication Mining Overview
• Why is it important?
• How can it help today’s business and the benefits
• Phases in Communication Mining
• Demo on Platform overview
• Q/A
Building RAG with self-deployed Milvus vector database and Snowpark Container...Zilliz
This talk will give hands-on advice on building RAG applications with an open-source Milvus database deployed as a docker container. We will also introduce the integration of Milvus with Snowpark Container Services.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!SOFTTECHHUB
As the digital landscape continually evolves, operating systems play a critical role in shaping user experiences and productivity. The launch of Nitrux Linux 3.5.0 marks a significant milestone, offering a robust alternative to traditional systems such as Windows 11. This article delves into the essence of Nitrux Linux 3.5.0, exploring its unique features, advantages, and how it stands as a compelling choice for both casual users and tech enthusiasts.
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
How to Get CNIC Information System with Paksim Ga.pptxdanishmna97
Pakdata Cf is a groundbreaking system designed to streamline and facilitate access to CNIC information. This innovative platform leverages advanced technology to provide users with efficient and secure access to their CNIC details.
4. do·main
dōˈmān n.
a sphere of knowledge,
influence, or activity
"domain." Merriam-Webster.com. 2011. http://www.merriam-webster.com/dictionary/domain (17 October 2011).
7. Elections vs. Referendums
Elections and referendums are not as similar as
they at first appear
Election winners may be determined by plurality
and/or winning threshold
Referendums can only be passed by meeting a
winning threshold
8. Local vs. Statewide Elections
Town Meeting Day (March) elections are very different than
statewide elections (November)
During statewide elections, voters may be voting in both local and
statewide elections at the same time—each with different district
boundaries
District boundaries dictate reporting needs—statewide elections
need to be reported one way, local elections another
9. Districts
Some districts may contain only part of a municipality or ward
The Chittenden-3-6 Vermont Representative District contains all
of Winooski and part of Burlington’s Ward 1
Citizens in this part of Burlington’s Ward 1 vote in Winooski for
statewide elections and in Burlington for local elections
Audience expects both aggregate and detailed reporting
Redistricting can occur between elections
12. Ames Room
Used in The Lord Of The
Rings: The Fellowship of
the Ring to make the
hobbits appear the
correct size in relation
to Gandalf
We are always using
mental models to
understand the world
around us—we do not
perceive an objective
reality
By Alex Valavanis (own work) [public domain], via Wikimedia Commons
13. "Why I prefer Fahrenheit to Celsius [Fixed]." reddit. 2012.
http://www.reddit.com/r/funny/comments/wigk1/why_i_prefer_fahrenheit_to_celsius_fixed/ (16 September 2012).
16. Software Practioner:
Edwin Catmull
Studied physics and computer science
Made many notable computer graphics discoveries
Eventually moved from two-dimensional to
three-dimensional animation
Hired by Lucasfilm to bring his expertise to the
entertainment field
17. Domain Expert:
John Lasseter
Studied animation and taught by veteran animators from Disney
Realized early-on the potential for computer generated imagery
Worked at, but eventually fired from, Disney
Hired by Edwin Catmull at Lucasfilm as an “Interface Designer”
because Catmull’s job didn’t include hiring animators[1]
1. Buckley, A. M. "Chapter 3: Art Meets Science." Pixar: The Company and Its Founders. Edina, MN: ABDO, 2011. 27. Print.
18. “Throughout the process, Lasseter
worked side-by-side with the computer
scientists. Lasseter’s requests pushed
them to develop new tools, and their
feedback helped him learn the digital
animation process.”[1]
1. Buckley, A. M. "Chapter 3: Art Meets Science." Pixar: The Company and Its Founders. Edina, MN: ABDO, 2011. 30. Print.
22. The Model
A model is an abstract set of tools that is used to
solve problems within a domain
While represented in code, do not think of the
model as just code
A “real world model” is a fool’s errand
The model must be explored collaboratively with
domain experts and software practitioners
23. “The map is not the territory.”
—Alfred Korzybski
24. Magritte, René. The Treachery of Images (La trahision des images). 1929. Oil on canvas. Los Angeles County Museum of Art, Los Angeles, California.
25. This is not a pipe.
Magritte, René. The Treachery of Images (La trahision des images). 1929. Oil on canvas. Los Angeles County Museum of Art, Los Angeles, California.
29. Bounded Context
Delineates the applicability of a particular model
Bounded contexts allow each model to be explored in isolation
Clearly define:
• Who is responsible for each bounded context
• To which parts of the application is the bounded
context applicable
• What manifestations the bounded context will take
(code, database schemas, etc.)
Document the interactions between bounded contexts
with a context map
30. Ubiquitous Language
Speak a ubiquitous language within a bounded context
Terms must be clearly defined, unambiguous, and consistent
Critically important when communicating between
domain experts and software practitioners
The ubiquitous language will (and must) evolve as a progressively
richer understanding of the domain and the model are achieved
If the ubiquitous language cannot be used to clearly express
complex ideas, then you have more work to do!
36. Entity
Defined by a thread of continuity and identity
Only responsibilities should be around identity and life cycle
May be composed of other entities and/or value objects
37. Value Object
Defined by its encapsulated attributes
Treat value objects as immutable
Delegate business logic to value objects
39. Aggregate
A group of related entities and value objects
Useful when defining transaction, distribution
and concurrency boundaries
A model will likely have multiple aggregates
40. Aggregate Root
Designate one entity as the aggregate root
Allow external references to only the aggregate root
Use unidirectional references within an aggregate root
for less complexity
• Example: Reference a line item’s order, or an order’s line items,
but not both
Maintain references on the “many” side of a “one-to-many”
relationships for less complexity:
• Example: Reference a line item’s order, rather than an order’s
line items
41. Repository
Delegate persistence of an aggregate root to a repository
A repository should behave as if it were an in-memory data store
If using an object-relational mapper (ORM):
Database -> ORM -> Repository
Use an in-memory strategy for unit tests
Straddles persistence and domain layers, allowing you to
stay focused on the domain model
42. Service
A place for operations that aren’t naturally part of
any domain object
Like value objects, services should be immutable
Operations on services are stateless
44. Commands & Queries
Commands are responsible for changing state
Queries are responsible for retrieving state
A commands may delegate the actual state change
to a domain event
45. Write Model/Read Model
Define one model for writing data (commands)
Define another model for reading data (queries)
Both models will likely share aggregate root entity identifiers
47. Domain Event
Something important that happens within the domain
that may lead to a state change in a domain object
Domain events can trigger other domain events (e.g.
three strikes triggers an out)
Domain events are immutable
Typically stored in an event log
48. Event Log
Current state can be computed by reading the event log
Retroactive events can be used to “fix” application state
Current state may be cached, if necessary for performance
Can also serve as an audit log
50. Closure of Operations
Have a method on a value object that returns an instance
of the same type of value object
Any method arguments should also be the same type as
the value object
Example: 2 + 3 = 5
• “2” is a value object of type integer
• integer has an add method
• add method accepts an argument of type integer
• add method returns an integer
• integers are closed under the operation of addition
53. Context Map
Draw a context map of the current bounded contexts
Map what actually exists—not what you wish existed!
Identify relationships between contexts
54. Relationship Patterns
customer/ anticorruption
partnership supplier layer
shared kernel big ball of separate ways
mud
open host conformist published
service language
56. Types of Domains
A model my represent:
• your core domain
• a supporting domain
• a generic subdomain
Focus your modeling efforts on the core domain
Consider outsourcing work on supporting domains
Consider off-the-shelf software for generic subdomains
57. Identifying the Core Domain
Ask organizational leaders and domain experts:
• What keeps you awake at night?
• What makes your system worth writing?
• Why not buy it off the shelf?
• Why not outsource it?
Is a telephone number an entity or a value object? In a CRM, it’s probably a value object. In a telephone company, a phone number may be an entity.\n
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Dates are another example of where closure of operations could be useful\n