How do in-memory databases work in SQLite?

Explanation & Concept

SQLite allows creating transient databases residing entirely in RAM by specifying `:memory:` as the database filename (or using memory URI filenames). In-memory databases are exceptionally fast and vanish completely when the connection closes.

Code Example

javascript

import Database from "better-sqlite3";

// Create in-memory SQLite database instance
const db = new Database(":memory:");

db.exec(`
  CREATE TABLE benchmarks (id INTEGER PRIMARY KEY, score REAL);
  INSERT INTO benchmarks (score) VALUES (98.6), (99.2);
`);

const rows = db.prepare("SELECT AVG(score) AS avgScore FROM benchmarks").get();
console.log("Memory DB Average:", rows.avgScore);

How It Works & Key Takeaways

In-memory databases provide ideal test fixtures for CI/CD test suites: each test run gets an isolated, ephemeral database without disk I/O cleanup.

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In-Memory DatabasesIntermediate

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javascript

How do in-memory databases work in SQLite?

Explanation & Concept

Code Example

javascript

import Database from "better-sqlite3";

// Create in-memory SQLite database instance
const db = new Database(":memory:");

db.exec(`
  CREATE TABLE benchmarks (id INTEGER PRIMARY KEY, score REAL);
  INSERT INTO benchmarks (score) VALUES (98.6), (99.2);
`);

const rows = db.prepare("SELECT AVG(score) AS avgScore FROM benchmarks").get();
console.log("Memory DB Average:", rows.avgScore);

How It Works & Key Takeaways

In-memory databases provide ideal test fixtures for CI/CD test suites: each test run gets an isolated, ephemeral database without disk I/O cleanup.

Mock Test · 1 Questions · Optional

Ready for Backup & Export?

Take a quick test to evaluate yourself, or move straight to the next module.

Intermediate1 questions

Skip