Data Modeling
30 bites tagged Data Modeling — interview questions with model answers, and 60-second explainers.
Describe the client-side event for an 'Add to Cart' button
Tests your knowledge of standard analytics schemas (like GA4) and designing payloads for business analysis. A great answer names the 'add_to_cart' event, details the 'items' array with product data, and mentions user/session context.
Nested Pydantic Models: Composing Complex Data
Use a Pydantic model as a field type inside another to build complex, nested structures. This is essential for modeling JSON with sub-objects, like a user with an address.
Fourth Normal Form (4NF): Isolating Independent Facts
4NF prevents storing independent, multi-valued facts in one table. It applies when a key relates to two unrelated lists, like a restaurant's pizza types and its delivery areas.
Surrogate Keys: Stable IDs for Unstable Data
A surrogate key is a meaningless, system-generated ID that never changes, unlike a 'natural' key (like an email) which can. Use it for stable joins between tables. The footgun is exposing these internal IDs in public URLs, which leaks data structure.
The Relational Model: Data as Simple Tables
The relational model organizes data into simple tables (relations) of rows (tuples), forming the foundation of SQL databases. It's used for structured data where consistency is critical, like in banking.
Querying NoSQL: It Depends on the Data Model
Querying NoSQL isn't one-size-fits-all; the method depends on the data model (key-value, document, graph). This is used for large, unstructured datasets like social feeds. The footgun is assuming SQL works everywhere; many require a model-specific API.
Get Data Modeling bites daily.
Five a day, five minutes, offline. With quizzes so it sticks.
Open testing — you’ll join as an early tester.