TOGAF® Standard, 10th Edition · OGEA-101 Foundation · Quick revision
Building Block
Official definition — learn word for word
“A potentially re-usable component that can be combined with other building blocks to deliver architectures and solutions.”
Building blocks can be defined at various levels of detail: at an early stage just a name or outline description; later decomposed into supporting building blocks with a full specification. They can relate to “architectures” (ABBs) or “solutions” (SBBs).
Source: CC §4.26 · CC §3.6
Memory aid
LEGO rule: a named brick with a clear edge, that can snap into others, and could be swapped out.
Memory aid — not TOGAF wording.
In plain words
A reusable piece of the enterprise — a process, application, data store or service — that can be combined with others.
Plain-English summary — not TOGAF wording.
Worked example
DUK's “student notification service” is built once and reused by admissions, exams and fees.
Illustrative example (Digital University Kerala) — not from the Standard.
01Mind map — related concepts
Building Block
TWO KINDS
ABB (architecture) · SBB (solution)
HAS
A type from the metamodel; a defined boundary
DETAIL GROWS
Name only → full specification
3 CLASSES
Re-usable · to develop · to purchase (COTS)
DESCRIBED BY
Artifacts (catalogs, matrices, diagrams)
NOT TO CONFUSE WITH
A deliverable or an artifact (a description)
Source: AC §5.2.2, §5.3.1 · CC §3.6
02Deliverable vs Artifact vs Building Block
| Type | What it is | Example |
|---|---|---|
| Deliverable | Contractually specified and formally reviewed, agreed, and signed off by the stakeholders | Architecture Definition Document |
| Artifact | Describes an aspect of the architecture; catalogs, matrices, diagrams | Process flow diagram |
| Building block | A potentially re-usable component combined with others to deliver architectures and solutions | Target call handling process; Customer Services Representative (actor) |
Deliverables contain artifacts; artifacts describe building blocks (CC Figs 3-2, 3-3).
Source: CC §3.6 · CC §4.23, §4.26, §4.40
03Building-block design (AC §5.3.1.2)
Look for collectionscapabilities or assets that interact with one another
Consider three classesre-usable (legacy) · to be developed · to be purchased (COTS)
Bind by integration levele.g. treat legacy as large blocks to avoid breaking them apart
Source: AC §5.3.1.2
04Where it appears in the ADM
Phases A–D
Building block definition takes place gradually, mainly in Phases A, B, C and D — evolutionary and iterative.
AC §5.3.2
Phases B–D · Step 3
Develop the view of required building blocks; fully document each; check against the building-block library in the Architecture Repository.
AC Fig 5-1
05Exam traps
“Every building block must be re-usable” → “Potentially re-usable” — ideally re-usable and replaceable
“A building block is a document” → Artifacts describe building blocks; deliverables contain artifacts
“A building block must always be fully specified” → Early on it can simply be a name or outline description
“An architecture should contain every building block available” → Only building blocks relevant to the business problem
“A building block's specification is tied to one implementation” → It should be loosely coupled so it can be realized in several ways
06Self-test — tap to reveal
Q1Define a building block.
A potentially re-usable component that can be combined with other building blocks to deliver architectures and solutions.
Q2Name the two kinds.
Architecture Building Blocks and Solution Building Blocks.
Q3What must a building block's interfaces be, where it interoperates?
Published and reasonably stable.
Q4Name the three classes considered in design.
Re-usable (e.g. legacy), to be developed, to be purchased (COTS).
Q5What describes building blocks?
Artifacts.
Q6Can a building block be decomposed?
Yes, into multiple supporting building blocks.
Q7What does a building block's type correspond to?
The metamodel (e.g. actor, business service, application, data entity).
Q8Which standard is cited as an example for formally describing building blocks?
OMG Re-usable Asset Specification (RAS).