What is Lightning Data Service (LDS) and when do you use it?

Lightning Data Service (LDS) is a Salesforce-managed cache and CRUD layer for record data, accessible from LWC without writing Apex.

LDS provides:

• `getRecord` — fetch a record's fields with cached, FLS-aware results.
• `getRecordCreateDefaults` / `getRecordUi` — get layout-aware metadata for record creation/edit.
• `createRecord` / `updateRecord` / `deleteRecord` — CRUD without Apex.
• `getRecordNotifyChange` — invalidate cache to force refresh.

import { LightningElement, wire } from 'lwc';
import { getRecord } from 'lightning/uiRecordApi';

const FIELDS = ['Account.Name', 'Account.Industry'];

export default class AccountView extends LightningElement {
  @api recordId;
  @wire(getRecord, { recordId: '$recordId', fields: FIELDS })
  account;
}

When to use LDS: simple read/edit on a single record, you want FLS/sharing automatically respected, you don't need cross-object queries.

When to use Apex instead: complex SOQL (joins, aggregates), cross-object logic, custom business rules before save, bulk operations, integrations.

Bonus: LDS shares its cache across all components on a page, so multiple components viewing the same record share data without duplicate API calls.