Search the practice set
275 questions, 991 terms and 600 topics in 30 areas.
38 results for “Dimensional Modelling”
Grain Declaration
Stating exactly what one row of a fact table represents, before any column is chosen, because every later decision depends on it.
Star Schema
A dimensional model with one central fact table of measurements surrounded by denormalised dimension tables describing them.
Access Pattern Driven Modelling
Designing the data model from the queries the application must serve, rather than from an abstract normalised representation of the entities.
Interaction Modelling
Showing the ordered exchange of messages between participants over time, to reason about protocols, failure points and latency.
Resource Modelling
Expressing an API as nouns with a consistent hierarchy rather than as verbs, so URLs are predictable and methods carry the semantics.
Threat Modelling
A structured exercise that identifies what can go wrong with a design, before it is built, by walking the system's trust boundaries.
Attack Surface
The complete set of points where an untrusted actor can interact with a system — and the quantity that reduction genuinely reduces risk.
Cost Model Sensitivity
Identifying which assumptions in a cost projection dominate the outcome, so effort goes into the estimates that actually matter.
Data-Flow Diagram
A diagram of how data moves between processes, stores and external entities, with trust boundaries drawn on it.
Demand Forecasting
Projecting future load from historical trends, business plans and known events, and translating it into resource requirements with explicit lead times.
Denormalisation
Deliberately duplicating data across records to make reads cheap, accepting the write-time cost of keeping copies in step.
Document Store
A store that keeps semi-structured documents — typically JSON — retrievable by key and queryable by their contents.
Domain-Driven Design
Modelling software around the business domain, with boundaries drawn where the language of the business changes.
Foreign Key Constraint
A database-enforced rule that a referencing value must exist in the referenced table — referential integrity that no application bug can violate.
Google Maps and Planetary-Scale Spatial Serving
Map serving is fast because almost nothing is computed on request — the world is precomputed into a pyramid of tiles, and space is indexed onto a one-dimensional curve.
Hub and Satellite
Separating stable business keys from their changing attributes and from their relationships, so each can be loaded independently and kept forever.
Normalisation
Organising a schema so each fact is stored exactly once, removing the update anomalies that duplication creates.
SQL vs NoSQL
A choice driven by access patterns, consistency requirements and query flexibility — not by data volume, which is the reason usually given.
STRIDE
A mnemonic for six threat categories — spoofing, tampering, repudiation, information disclosure, denial of service, elevation of privilege — walked across each component and data flow.
Subject Naming Strategy
How schemas are keyed in a registry — per topic, per record type, or both — which determines whether one topic may carry several event types.
Surrogate Key
A system-generated identifier with no business meaning, used as the primary key instead of a naturally occurring business value.
Vector Database
A store optimised for approximate nearest-neighbour search over high-dimensional embeddings.
A finance report double-counts revenue after a new fact table is added. What is the likely modelling error?
The likely error: a fan out join between fact tables at different grains The classic mechanism. You have an order lines fact at line grain and a shipments fact
A team proposes storing the customer's address on every order row "so order history is accurate". Is that denormalisation or a modelling error?
The distinction that matters It is neither, quite — it is a temporal modelling requirement being solved by accident. Denormalisation duplicates a fact for perfo
A document collaboration product needs sharing with individuals, teams, and inherited folder permissions. Which authorization model?
The requirement is relationship shaped The questions this product must answer are: is this user a member of a team that has access to a folder that contains thi
A transformation project has grown to 600 models with chains twelve deep. A change at the base has an unknowable blast radius. What do you do?
Treat it as a software architecture problem, because it is one Six hundred models with twelve deep chains is a codebase with no module boundaries. The remedies
Discord stores trillions of messages. What is their partition key, and what problem does the second half of it solve?
The key (channel id, bucket) — where bucket is a fixed time window. What each half does channel id matches the read pattern. Clients read messages within a chan
Run a threat model on a new payment integration: our service calls a third-party payment provider and receives webhooks. Where are the interesting threats?
Draw the boundaries first Three trust boundaries, and nearly every interesting threat lives on one of them: 1. User → our service (untrusted input, authenticate
Dimensional Modelling
Facts, dimensions, grain, and the star schema's continued relevance.
Data Warehousing
Dimensional modelling, star schemas and analytical workloads.
Architecture Cost Modelling
Pricing a design before building it, at expected and at ten times volume.
Capacity Modelling
Arithmetic before load tests, and headroom for failure as well as peak.
Data Vault Modelling
Hubs, links and satellites, and the auditability and load parallelism they buy.
Relational Modelling
Normalisation, keys, constraints and the invariants a schema enforces.
Threat Modelling
Walking trust boundaries with STRIDE before anything is built.