Scope
Compared
- Whether each governs one codebase or the organization's operational record
- How each treats identity and language across system boundaries
- Where each discipline's authority actually ends
Not compared
- DDD's tactical patterns (Repository, Factory, Specification pattern)
- Specific implementation frameworks or languages
- Event sourcing or CQRS as architectural choices
Terminology mapping
| OCOM | DDD | Equivalent |
|---|---|---|
| Object | Aggregate | Partial |
| Core Vocabulary | Ubiquitous Language | Partial |
| Domain | Bounded Context | Partial |
| Event | Domain Event | Partial |
| — | Repository (pattern) | None |
Conceptual differences
| Aspect | OCOM | DDD |
|---|---|---|
| Centre of gravity | Object-centric: what the organization governs | Context-centric: how one system's code is structured |
| Time | Object state over the whole lifecycle | Aggregate consistency within a transaction |
| Governance | First-class: ownership, policy, constraint | Context maps govern model boundaries and team ownership, not operational accountability |
| Scope | Spans systems and technologies | Bounded to one model and language boundary (a bounded context) |
Concept coverage
| Concept | OCOM | DDD |
|---|---|---|
| Software design guidance | Out of scope | Covered |
| Object identity | Covered | Partial |
| Lifecycle | Covered | Partial |
| Governance | Partial | Out of scope |
| Ownership | Covered | Partial |
| Evidence | Partial | Out of scope |
| AI retrieval | Partial | Out of scope |
Three OCOM cells read Partial rather than Covered (Governance, Evidence, AI retrieval), and the reason for each is recorded in the specification's own register: Governance is a Core Characteristic of every Object that no document defines as one (AO-023); Evidence has no Meta, Models or Language definition, its Definition being reserved for a future version (AO-021); AI retrieval is disclaimed by AI/Context/Context Assembly.md, which prescribes no retrieval algorithms (AO-048). Workflow and Event are defined normatively at the Models tier and carry no Core Vocabulary term record.
Covered: the model defines the concept explicitly. Partial: the concept appears indirectly or by convention. Out of scope: the model does not set out to describe it; a boundary, not a deficiency.
Interoperability
- A DDD bounded context can implement a slice of an OCOM model.
- OCOM identities give separate bounded contexts a shared anchor: the "customer" in two contexts keeps its own model in each, while resolving to one governed Identity.
References
- OCOM Object
- OCOM Identity
- OCOM Relationship
- Domain-Driven Design, Eric Evans (2003)