Bounded context mapping in Microservices - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a bounded context in system design?

A bounded context is a clear boundary within a system where a particular domain model applies consistently. It defines where specific terms and rules have a single meaning.

beginner

Why do we use bounded context mapping in microservices?

We use bounded context mapping to divide a large system into smaller, manageable parts. Each part has its own model and language, reducing confusion and making services easier to build and maintain.

intermediate

Name two common relationships between bounded contexts.

Two common relationships are: 1) Shared Kernel - sharing a small part of the model between contexts, and 2) Customer-Supplier - one context depends on another's output.

intermediate

What is the difference between 'Open Host Service' and 'Published Language' in bounded context mapping?

'Open Host Service' is a well-defined interface for other contexts to interact with, while 'Published Language' is a shared language or protocol used for communication between contexts.

intermediate

How does bounded context mapping help avoid integration problems?

By clearly defining boundaries and communication patterns, bounded context mapping prevents misunderstandings and conflicts between teams and services, leading to smoother integration.

What does a bounded context primarily define?

A A database schema shared by all services

B A user interface design pattern

C A clear boundary where a domain model applies consistently

D A network protocol for communication

A bounded context defines a clear boundary where a specific domain model and language apply consistently.

Which relationship involves sharing a small part of the model between bounded contexts?

A Customer-Supplier

B Shared Kernel

C Conformist

D Anticorruption Layer

Shared Kernel means sharing a small, agreed-upon part of the model between contexts.

What is an 'Open Host Service' in bounded context mapping?

A A well-defined interface for other contexts

B A user interface component

C A database replication method

D A logging service

Open Host Service is a clear interface that other bounded contexts can use to interact.

Why is bounded context mapping important in microservices?

A To enforce a single programming language

B To create a single large database

C To speed up network communication

D To reduce confusion by defining clear boundaries

Bounded context mapping reduces confusion by defining clear boundaries and models for each service.

Which pattern helps protect one bounded context from changes in another?

A Anticorruption Layer

B Customer-Supplier

C Open Host Service

D Shared Kernel

Anticorruption Layer acts as a translator to protect one context from changes in another.

Explain what bounded context mapping is and why it is useful in microservices.

Think about how dividing a big system into smaller parts helps teams work better.

Describe at least three types of relationships between bounded contexts and their purpose.

Consider how contexts share data or protect themselves from changes.

Practice

1. What is the main purpose of bounded context mapping in microservices architecture?

easy

A. To divide a system into clear, manageable parts with defined boundaries

B. To merge all services into a single large application

C. To increase the number of database tables in a system

D. To remove communication between different teams

Solution

1. Step 1: Understand bounded context concept

   Bounded context means splitting a system into parts that have clear boundaries and responsibilities.

2. Step 2: Identify the main goal of mapping

   Mapping helps teams work independently and reduces complexity by defining these boundaries.

3. Final Answer:

   To divide a system into clear, manageable parts with defined boundaries -> Option A

4. Quick Check:

   Bounded context = clear system parts [OK]

Hint: Bounded context means clear boundaries in system parts [OK]

Common Mistakes:

• Thinking bounded context merges services
• Confusing bounded context with database design
• Assuming it removes team communication

2. Which of the following correctly represents a relationship type in bounded context mapping?

easy

A. Customer/Supplier means contexts never communicate

B. Shared Kernel means two contexts share a small part of their domain model

C. Open Host Service means one context copies all data from another context

D. Conformist means contexts ignore each other's models completely

Solution

1. Step 1: Review relationship types in bounded context mapping

   Shared Kernel means two contexts share a small, common part of their domain model to stay consistent.

2. Step 2: Check other options for correctness

   Open Host Service is about providing a stable interface, not copying all data. Customer/Supplier implies communication. Conformist means one context adapts to another's model, not ignoring it.

3. Final Answer:

   Shared Kernel means two contexts share a small part of their domain model -> Option B

4. Quick Check:

   Shared Kernel = shared small domain part [OK]

Hint: Shared Kernel means sharing a small model part [OK]

Common Mistakes:

• Confusing Open Host Service with data copying
• Thinking Customer/Supplier means no communication
• Believing Conformist ignores other models

3. Given two bounded contexts A and B where A is the Customer and B is the Supplier, what is the expected interaction pattern?

medium

A. Context B provides services that Context A consumes

B. Context A adapts to B's model without changes

C. Contexts A and B share the same database schema

D. Contexts A and B never exchange data or messages

Solution

1. Step 1: Understand Customer/Supplier relationship

   In this pattern, the Supplier context offers services or data that the Customer context uses.

2. Step 2: Analyze options

   Context A adapts to B's model without changes describes Conformist, not Customer/Supplier. Contexts A and B share the same database schema is incorrect because sharing the same database schema breaks bounded context boundaries. Contexts A and B never exchange data or messages contradicts the relationship.

3. Final Answer:

   Context B provides services that Context A consumes -> Option A

4. Quick Check:

   Customer/Supplier = Supplier provides services [OK]

Hint: Supplier provides, Customer consumes services [OK]

Common Mistakes:

• Mixing Customer/Supplier with Conformist
• Assuming shared database schema
• Thinking no data exchange happens

4. You have two bounded contexts with a Conformist relationship, but the Customer context is modifying the Supplier's domain model directly. What is the problem?

medium

A. The Conformist pattern requires sharing the same database schema

B. The Supplier context must always copy the Customer's model

C. Both contexts should merge into one to avoid conflicts

D. The Customer context should not change the Supplier's model; it should adapt to it

Solution

1. Step 1: Understand Conformist relationship rules

   In Conformist, the Customer context adapts to the Supplier's model but does not modify it directly.

2. Step 2: Identify the error in modifying Supplier's model

   Modifying the Supplier's model breaks the boundary and can cause inconsistencies.

3. Final Answer:

   The Customer context should not change the Supplier's model; it should adapt to it -> Option D

4. Quick Check:

   Conformist means adapt, not modify [OK]

Hint: Customer adapts Supplier model, does not modify it [OK]

Common Mistakes:

• Thinking Supplier copies Customer model
• Merging contexts unnecessarily
• Assuming shared database schema is required

5. You are designing a large e-commerce system with multiple teams. How should you apply bounded context mapping to ensure scalability and team independence?

hard

A. Ignore context boundaries and let teams decide data sharing ad hoc

B. Combine all domains into one large context to simplify communication

C. Define clear bounded contexts for domains like Orders, Payments, and Inventory, and map their relationships explicitly

D. Allow teams to share a single database schema to avoid data duplication

Solution

1. Step 1: Identify the need for clear domain boundaries

   Large systems benefit from dividing domains like Orders, Payments, and Inventory into separate bounded contexts.

2. Step 2: Map relationships explicitly for team independence

   Explicit mapping helps teams understand dependencies and communicate properly without tight coupling.

3. Step 3: Avoid combining domains or sharing schemas

   Combining domains or sharing schemas increases complexity and reduces scalability.

4. Final Answer:

   Define clear bounded contexts for domains like Orders, Payments, and Inventory, and map their relationships explicitly -> Option C

5. Quick Check:

   Clear contexts + explicit mapping = scalable teams [OK]

Hint: Clear contexts and explicit maps enable scalable teams [OK]

Common Mistakes:

• Merging all domains into one context
• Sharing a single database schema
• Ignoring boundaries and ad hoc sharing