Glossary

A

Actor

A role, team, organization, person type, or system role that initiates commands or asks queries.

Aggregate

A consistency boundary that receives commands, enforces invariants, and emits domain events. An aggregate is not simply a database table.

Aggregate Root

The main entity through which outside code interacts with an aggregate. Commands should target the aggregate root rather than changing child entities directly.

B

Bounded Context

A boundary where a model and its language have a clear meaning. Different contexts can use the same word differently.

Business Rule

A rule from the domain that constrains what the system may do.

C

Command

An intent to change the system, named as an imperative verb phrase such as Approve Claim.

Command Handler

The generated application layer code that receives a command and coordinates validation, aggregate loading, decision execution, and persistence.

Compensation

A follow-up action that mitigates a previous step when a long-running process cannot complete as planned.

CQRS

Command Query Responsibility Segregation. A design approach that separates operations that change state from operations that read state.

CRUD

Create, read, update, and delete. A good fit for simple record maintenance systems.

D

Domain

The business area the software supports, such as insurance claims, subscription billing, logistics dispatch, or appointment scheduling.

Domain Event

A meaningful business fact that happened, named in the past tense, such as Payment Authorized.

Domain Expert

A person who understands the business rules, language, exceptions, and real-world process.

Domain-Driven Design

A software design approach that models complex business domains around language, boundaries, and behaviour.

E

Entity

A domain object with identity over time.

Event Sourcing

A persistence style where meaningful events are stored as the record of change, and current state can be derived from those events.

EventStorming

A collaborative modelling approach that explores a domain by discovering events, commands, policies, actors, systems, and boundaries.

External System

A system outside the generated boundary that exchanges data, commands, or events with the modelled system.

H

Hotspot

A visible question, uncertainty, risk, disagreement, or missing decision on the canvas.

I

Idempotency

The ability to handle duplicate commands or messages without applying the same business effect twice.

Integration Event

An event intentionally published across a system or bounded-context boundary.

Invariant

A rule that must remain true inside a boundary, usually enforced by an aggregate.

P

Policy

An event-driven rule that reacts to something that happened and may trigger a command.

Projection

The process or generated handler that updates a read model from events.

Q

Query

A request for information that does not change business state.

R

Read Model

Information shaped for a screen, query, report, policy, dashboard, or integration.

S

SAAScade Cloud

The hosted environment where Code Genie can deploy generated systems for teams that want managed hosting.

Saga

A long-running workflow coordinator that tracks steps across events, commands, time, and systems.

U

Ubiquitous Language

The shared vocabulary used by domain experts, product teams, architects, and developers.

V

Value Object

A descriptive object defined by its values rather than identity, such as Money, Address, Date Range, or Email Address.