Patterns

Entity

The Entity pattern represents a real-world object with a distinct identity that persists over time. Entities are defined by their attributes and behaviors, but crucially, they are distinguished from Value Objects by having a unique identifier (ID) that remains constant even if their attributes change. This identity …

Materialized View

behavioral performance

The Materialized View pattern is a way to optimize read performance by precomputing and storing the results of complex or frequently used queries. Instead of re-executing these queries every time they are needed, the precomputed results are retrieved directly from the materialized view, dramatically reducing latency. …

Projection

behavioral data

The Projection pattern addresses the problem of efficiently delivering only the data required by a client or use case, preventing over-fetching and improving performance. Instead of exposing the entire data model, a projector transforms the source data into a simplified data view specifically tailored for the consumer. …

Bounded Context

DDD strategic

A Bounded Context is a central concept in Domain-Driven Design. It defines an explicit boundary within which a particular domain model applies. Within a Bounded Context, a specific set of terms and concepts have a precise and consistent meaning. Outside that boundary, those terms may have different meanings, or be …

Builder

creational

The Builder pattern is a creational design pattern that lets you construct complex objects step-by-step. It allows customization of the object being built without making the construction process itself complex and unmanageable. The pattern separates the construction of a complex object from its representation, so the …

Chain of Responsibility

behavioral GoF

The Chain of Responsibility is a behavioral design pattern that allows you to pass a request along a chain of handlers. Each handler decides either to process the request or to pass it to the next handler in the chain. This pattern decouples the sender of a request from its receivers, giving multiple objects the …

Event Sourcing

behavioral DDD persistence

Event Sourcing is a pattern where the state of an application is determined not by directly storing the current state, but by storing a sequence of all the changes (events) that have occurred. Instead of asking “what is the data now?” you ask “what happened then?” and rebuild the state from the …

Flyweight

creational

The Flyweight pattern is a structural design pattern that aims to minimize memory usage or computational costs by sharing as much data as possible between similar objects. It achieves this by separating the object state into intrinsic and extrinsic parts. Intrinsic state is shared and immutable, held within the …

Identity Map

behavioral data access

The Identity Map pattern ensures that each object has a unique representation in memory. It maintains a registry of objects already loaded from the database, and when an object is requested, the map checks if it already exists before retrieving it from the persistence store. This reduces memory consumption and improves …

Row Data Gateway

creational data access

The Row Data Gateway pattern provides an interface to a database table. It encapsulates all the direct database access logic and exposes methods to perform operations on the table rows as objects. The gateway maps rows from one or more tables to objects, effectively presenting a higher-level, object-oriented view of …