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CRUD operations

CRUD stands for create, read, update, delete: the four things every app does with stored data.

In this page:

  1. CRUD operations

CRUD operations

Wrap CRUD in a small data layer so routes stay simple. Whatever the database, the operations are the same ideas: insert a record, query records, change a record and remove one. Return meaningful results and handle not-found cases.

Note: Keep database code in one module so you can swap the database later.

Example: CRUD operations

javascript
class Store {
  constructor() { this.rows = new Map(); this.next = 1; }
  create(data) { const row = { id: this.next++, ...data }; this.rows.set(row.id, row); return row; }
  read(id) { return this.rows.get(id) || null; }
  update(id, patch) { const r = this.read(id); if (!r) return null; Object.assign(r, patch); return r; }
  remove(id) { return this.rows.delete(id); }
}
const s = new Store();
const u = s.create({ name: "Ada" });
console.log(s.read(u.id));
console.log(s.update(u.id, { name: "Ada L." }));
console.log(s.remove(u.id), s.read(u.id));

// Output:
// { id: 1, name: 'Ada' }
// { id: 1, name: 'Ada L.' }
// true null

⚠️ Run this in your own terminal or Node.js environment.

Related Topics
Common Mistakes
  1. Scattering queries across route handlers
  2. Not handling missing records
  3. Forgetting to validate input
Chapter Summary
  • Create, read, update, delete
  • Keep data access in one layer
  • Handle not found
  • Validate input
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