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All fields Software Mathematics Physics Chemistry Biology Engineering Astronomy Environmental Other Software Software groups

Explore STEM Content

Search the community's STEM library — free to study, yours to make your own.

Software

Programming, algorithms and systems on openstem — flashcards, notes, quizzes, sketches and flowcharts shared by the community. Study free, or clone anything into your library.

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Software: explore STEM content (page 5 of 25) · openstem

Quiz10 questions

Which clause filters rows AFTER aggregation?

AWHEREBHAVINGCGROUP BYDORDER BY

Software

Software · L4 · SQL fundamentals — 10 Q

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Software · L4 · SQL fundamentals — 10 Q

Quiz5 questions

What does this log?

AA, B, C, DBA, D, C, BCA, D, B, CDD, C, B, A

Software

Software · L2 · JavaScript: Event Loop Order

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Software · L2 · JavaScript: Event Loop Order

Flowchart11 objects

Software

Software · L2 · SQL: Isolation Levels & Locking · flowchart

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Software · L2 · SQL: Isolation Levels & Locking · flowchart

Collection5 items

01Layout & Constraints

02Navigation & Routing

03State Management

+2 more

Software

Software · L2 · Flutter

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Software · L2 · Flutter

Note~162 words · 1 min

Mapping Entities and Relationships A JPA entity is a POJO annotated `@Entity` with an `@Id` field, mapped to a database table. Relationships between entities are declared with annotations rather than manual join SQL. Why @Transactional Matt

Software

Software · L2 · Spring Boot: Data Access & Transactions

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Software · L2 · Spring Boot: Data Access & Transactions

Flashcards10 cards

What is logged?1 / 10

false — floating-point rounding makes 0.1 + 0.2 = 0.30000000000000004.

Software

Types & Coercion

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Types & Coercion

Quiz8 questions

What does the Hoare triple {P} C {Q} assert about a program C that never terminates from some P-satisfying state?

AThe triple is falseBThe triple is vacuously true, since partial correctness only constrains terminating executionsCThe triple is undefinedDQ must be false

Software

Software · L5 · Hoare Logic & Program Verification

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Software · L5 · Hoare Logic & Program Verification

Flashcards10 cards

What annotation is the typical entry point of a Spring Boot application?1 / 10

`@SpringBootApplication`, a meta-annotation combining `@Configuration`, `@EnableAutoConfiguration`, and `@ComponentScan`.

Software

Spring Boot & Autoconfiguration

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Spring Boot & Autoconfiguration

Quiz5 questions

Why must the server hash the incoming password before comparing it, rather than storing and comparing plaintext?

AHashing makes login fasterBIf the database leaks, hashed passwords can't be immediately used, unlike plaintextCHashing is required by HTTPSDIt lets users log in without a password

Software

Software · L1 · Security & Auth: Login & Session Flow

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Software · L1 · Security & Auth: Login & Session Flow

Note~154 words · 1 min

Why Creational Patterns Exist Creational patterns all deal with the same underlying question — how should an object come into existence? — but they answer it differently depending on what makes construction hard: uniqueness, complexity, var

Software

Software · L1 · Design Patterns: Choosing a Creational Pattern

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Software · L1 · Design Patterns: Choosing a Creational Pattern

Flashcards10 cards

What is a Server Action in Next.js?1 / 10

An async function marked with 'use server' that runs on the server but can be invoked directly from client components (e.g. in a form action or event handler). It eliminates manually writing API routes for mutations — Next handles the RPC.

Software

Data & Optimization

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Data & Optimization

Flashcards10 cards

What kind of system is BigQuery?1 / 10

BigQuery is a serverless, columnar, fully managed data warehouse that separates storage from compute and scales queries automatically.

Software

Data & Analytics (BigQuery)

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Data & Analytics (BigQuery)

Collection4 items

01Core Services

02Cloud Fundamentals

03Software · L1 · AWS: Storage Options Compared

+1 more

Software

Software · L1 · AWS

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Software · L1 · AWS

Flowchart10 objects

Software

Software · L1 · MongoDB: Schema Design — Embedding vs Referencing · flowchart

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Software · L1 · MongoDB: Schema Design — Embedding vs Referencing · flowchart

Flowchart30 objects

Software

Software · L3 · GraphQL Request Lifecycle

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Software · L3 · GraphQL Request Lifecycle

Flashcards10 cards

What is the Adapter pattern?1 / 10

Wraps an incompatible interface so it can be used where a different interface is expected — a translator between two APIs. Lets you integrate legacy or third-party code without changing it.

Software

Structural Patterns

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Structural Patterns

Flashcards10 cards

What is a Web Worker and what can it NOT do?1 / 10

A Web Worker runs JS in a background thread, keeping the main thread free. It CANNOT access the DOM, window, or main-thread variables directly. Communication is via `postMessage`/`onmessage` with structured-clone data copying.

Software

Concurrency & Advanced Patterns

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Concurrency & Advanced Patterns

Collection2 items

01Storage Engine, Indexing & Query Internals

02Replication, Sharding & Consistency

Software

Software · L4 · MongoDB

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Software · L4 · MongoDB

Quiz10 questions

What does the Singleton pattern ensure?

AA class can be subclassed only onceBA class has at most one instance and provides a global access pointCAn object can only be created by a factoryDAll methods are static

Software

Software · L4 · Design patterns — 10 Q

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Software · L4 · Design patterns — 10 Q

Flashcards10 cards

How does Anycast route a client to the nearest CDN edge?1 / 10

Anycast advertises the same IP prefix via BGP from many locations. The internet's routing fabric naturally delivers each client's packets to the topologically nearest advertising node, providing built-in proximity routing and DDoS dispersion.

Software

CDNs, Anycast & BGP

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CDNs, Anycast & BGP

Flashcards10 cards

What is prop drilling and how do you solve it?1 / 10

Passing props through many intermediate components that don't use them — just to reach a deeply nested child. Solve with React Context, a state management library (Zustand, Redux), or component composition.

Software

State & Context

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State & Context

Flowchart17 objects

Software

Software · L1 · NestJS: Request Lifecycle · flowchart

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Software · L1 · NestJS: Request Lifecycle · flowchart

Flashcards9 cards

How are optional named parameters declared in a Dart function?1 / 9

They are wrapped in `{ }` in the signature, e.g. `void f({int x = 0})`. Callers pass them by name, and each may have a default or be marked `required`.

Software

Control Flow & Functions

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Control Flow & Functions

Flashcards10 cards

What is a race condition?1 / 10

A bug where the program's correctness depends on the nondeterministic timing or interleaving of concurrent operations on shared state.

Software

Deadlocks & Race Conditions

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Deadlocks & Race Conditions

Flashcards9 cards

What is the difference between REST and GraphQL?1 / 9

REST uses multiple fixed endpoints (one per resource); GraphQL uses a single endpoint where clients specify exactly the data they need. GraphQL avoids over-fetching and under-fetching but adds complexity. REST is simpler and has better HTTP caching.

Software

APIs & Protocols

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APIs & Protocols

Flashcards9 cards

What is the difference between a process and a thread?1 / 9

A process is an independent program with its own memory address space. A thread is a unit of execution within a process; threads of the same process share memory and resources. Threads are cheaper to create and switch between, but share state (needing synchronization).

Software

Processes & Threads

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Processes & Threads

Collection2 items

01Compiler & Config

02Advanced Patterns

Software

Software · L4 · TypeScript

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Software · L4 · TypeScript

Quiz5 questions

You need multi-table joins and strong ACID transactions for financial records. Which database type fits best?

ARelational (SQL)BKey-value storeCGraph databaseDDocument database

Software

Software · L1 · System Design: Choosing a Database Type

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Software · L1 · System Design: Choosing a Database Type

Flashcards8 cards

What are the building blocks of a NestJS application?1 / 8

Modules (organize related code), Controllers (handle incoming requests and routing), and Providers/Services (business logic, injectable). Nest wires them via a built-in dependency injection container — a structured, Angular-inspired architecture.

Software

Architecture

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Architecture

Quiz5 questions

Which caching strategy gives the strongest consistency between cache and database?

AWrite-throughBWrite-backCCache-aside with a long TTLDNo caching at all is more consistent

Software

Software · L2 · System Design: Choosing a Cache Strategy

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Software · L2 · System Design: Choosing a Cache Strategy

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