---
title: "Short note: Design patterns in deployment"
subject: "Object Oriented Analysis and Design"
chapter: 3
key: "semester_6/object_oriented_analysis_and_design:short-note-design-patterns-deployment"
source: https://www.bctengineer.com/q/semester_6/object_oriented_analysis_and_design/short-note-design-patterns-deployment
site: BCT Engineering
---

# Short note: Design patterns in deployment

Object Oriented Analysis and Design · Chapter 3: Object Oriented Design

- Asked in: 2070 Magh, 4 marks
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/object_oriented_analysis_and_design/short-note-design-patterns-deployment
- Whole chapter: https://www.bctengineer.com/md/semester_6/object_oriented_analysis_and_design/chapter-3

## Question

Write a short note on Effect of design patterns in deployment.

## Short answer

Design patterns improve deployment by enabling clean layered architecture (Facade, Layers), independent component deployment (Proxy, Broker, DAO), runtime configuration via Strategy/Factory, resource efficiency (Singleton, Flyweight, Pool), and maintainability through shared vocabulary. However, misuse adds indirection and complexity.

## Answer

(Interpreted as the effect of using design patterns when the system is implemented and deployed.)

Design patterns are proven solutions to recurring design problems. Their use has these effects on development and deployment:

1. **Better structure and quality.** Patterns such as Facade, Layers and Factory give a clean architecture; the system is loosely coupled, so components can be installed, replaced or upgraded independently.
2. **Easier distribution and deployment.** Patterns like Proxy, Broker, Facade and Data Access Object separate the client from the server or database, so tiers (presentation, business, data) can be deployed on different nodes with little change in code.
3. **Flexibility and configuration.** Strategy, Factory and Abstract Factory allow behaviour or the database/driver to be chosen by configuration at deployment time without recompiling.
4. **Scalability and performance.** Singleton, Flyweight, Object Pool and Cache reduce resource use; Observer/Publisher-Subscriber supports distributed updates.
5. **Maintenance and communication.** Because patterns are well-known, deployed systems are easier to understand, test and maintain; documentation uses a shared vocabulary.
6. **Possible costs.** Misuse adds extra classes, indirection and a performance overhead, and increases complexity for small systems.

```text
 Client --> [Proxy/Facade] --> [Business tier] --> [DAO] --> DB
   (node 1)       (node 2)          (node 3)       (node 4)
```

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. How do Proxy, Facade and DAO help deployment?
   A. They merge all tiers into one
   B. They remove the database
   C. They force one server only
   D. They separate client from server/database so tiers can sit on different nodes
   Answer: D. These patterns decouple tiers so they can be deployed on different nodes with little code change. (Key point: Tiered deployment)

2. Which patterns let behaviour or the database driver be chosen by configuration without recompiling?
   A. Strategy, Factory and Abstract Factory
   B. Singleton only
   C. Observer only
   D. None
   Answer: A. Strategy and factories choose implementations at deployment through configuration. (Key point: Configuration at deployment)

3. What is a possible cost of misusing patterns?
   A. Fewer classes
   B. Extra classes, indirection, overhead and complexity
   C. Tighter coupling always
   D. Impossible deployment
   Answer: B. Misuse adds indirection and complexity, especially in small systems. (Key point: Costs of patterns)

## Related in Object Oriented Analysis and Design

- [Deployment diagram as class diagram of nodes](https://www.bctengineer.com/question.md?key=semester_6%2Fobject_oriented_analysis_and_design%3Adeployment-diagram-special-class-diagram) — Object Oriented Analysis and Design, chapter 3
- [Pattern vs framework; GRASP patterns](https://www.bctengineer.com/question.md?key=semester_6%2Fobject_oriented_analysis_and_design%3Apattern-vs-framework-grasp) — Object Oriented Analysis and Design, chapter 3
- [Pattern based design and benefits](https://www.bctengineer.com/question.md?key=semester_6%2Fobject_oriented_analysis_and_design%3Apattern-based-design-benefits) — Object Oriented Analysis and Design, chapter 3

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