Apr 17 · 10 min read · Source: Ways to Handle Schema Evolution Safely in Production Systems The first time a seemingly tiny schema change caused an outage in my team, it wasn't because the change was technically hard — it was because we had focused only on the "happy pat...
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Feb 1 · 3 min read · DTO Pattern은 어디서 시작됐을까? DTO Pattern은 Sun Microsystems의 J2EE Core Patterns에서 공식적으로 정리된 개념이다. (2001년 초판: Core J2EE Patterns) 최초 DTO는 분산 환경(EJB, RMI)에서 원격 호출 횟수를 줄이기 위한 목적으로 정의되었다. 이 개념을 2002년 마틴 파울러가 Patterns of Enterprise Application Architecture 책에서 ...
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Jan 21 · 6 min read · Source: Techniques to Master Low-Level Design in OOP: Understanding Association, Aggregation, Composition, and Dependency with UML and Java Examples for Interview 1. Introduction: Why Low-Level Design Matters 1.1 Understanding Association in U...
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Jan 9 · 12 min read · Source: Techniques to Map Request DTOs, Commands, and Domain Models in DDD + Hexagonal Architecture 1. The mental model: DTOs describe intent, Commands capture decisions, Domain enforces invariants A Request DTO is a transport shape optimized ...
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Dec 13, 2025 · 3 min read · 在資安領域有一個非常有名的概念叫做 Zero Trust (零信任)。它的核心精神只有一句話："Never Trust, Always Verify" (永不信任，始終驗證)。 在網路世界裡，後端工程師的第一條守則是：「永遠不要相信客戶端傳來的輸入」。 過去工程師常認為：「只要使用者登入了（通過驗證），他傳來的資料就是安全的」或者「這是我們自己寫的前端 App 傳來的資料，所以可以信任」。這就是傳統的邊界防禦 (Perimeter Security) 思維——就像城堡，進了城門就沒人管你了。 但...
Join discussionNov 18, 2025 · 2 min read · What is Data Transfer Objects? A Data Transfer Object (DTO) is a simple object used to pass data from one part of an application to another, or even between different applications or systems. A Data Transfer Object (DTO) is a simple object used to ...
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Nov 2, 2025 · 3 min read · We have already discussed about the DTO classes and the mappers required for the Image Response API. Please checkout chapter 6 to recap the code. The ImageResultDto and ImageResponseDto data classes showcase our DTO. The DTO to Domain layer mapper fu...
Join discussionOct 28, 2025 · 6 min read · We coded the domain layer classes in the earlier chapter. Now we need to write the classes of data layer so that the use case becomes more meaningful in nature. The GetArtUseCase will fetch the list of Art objects from the local Room database. This i...
Join discussionOct 12, 2025 · 8 min read · only show the basic steps, as for the other part, version control, CICD, Unit Test, just let it alone, we will focus on the basic structure of the project and the optimise of our code. initial project architecture design CQRS, DDD, ES EF and DTO m...
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