# Updating Records

Use the `update` method on your `Locality` instance to modify existing rows in a table.

## Update with Condition

To update rows that match a specific filter, chain `set()` and `where()` followed by `run()`. The return value is the number of rows updated:

```typescript
// Update by predicate condition
const updatedCount = await db
  .update('users')
  .set({ name: 'Jane Doe', age: 30 })
  .where((user) => user.id === 1)
  .run();

console.log(`Updated ${updatedCount} records`);
```

## Index-Based Filtering (Optimized)

You can also use an index name or primary key for the update query's `where()` condition to speed up execution:

```typescript
const updatedCount = await db
  .update('users')
  .set({ isActive: true })
  .where('email', 'alice@example.com')
  .run();
```

## Computed Updates

Instead of passing a static object, you can pass a callback function to `set()`. The function receives the current row state and returns the fields to update:

```typescript
const computedCount = await db
  .update('users')
  .set((row) => ({
    name: row.name + ' Updated',
    age: row.age + 1,
  }))
  .where('id', 1)
  .run();
```

## Update All Matching Records

If your condition matches multiple rows, they will all be updated:

```typescript
await db
  .update('users')
  .set({ isActive: false })
  .where((user) => user.lastLogin < '2025-01-01')
  .run();
```