Some D1 Worker Binding APIs return a typed object.

| D1 Worker Binding API | Return object |
| - | - |
| [`D1PreparedStatement::run`](https://developers.cloudflare.com/d1/worker-api/prepared-statements/#run), [`D1Database::batch`](https://developers.cloudflare.com/d1/worker-api/d1-database/#batch) | `D1Result` |
| [`D1Database::exec`](https://developers.cloudflare.com/d1/worker-api/d1-database/#exec) | `D1ExecResult` |

## `D1Result`

The methods [`D1PreparedStatement::run`](https://developers.cloudflare.com/d1/worker-api/prepared-statements/#run) and [`D1Database::batch`](https://developers.cloudflare.com/d1/worker-api/d1-database/#batch) return a typed [`D1Result`](#d1result) object for each query statement. This object contains:

* The success status
* A meta object with the internal duration of the operation in milliseconds
* The results (if applicable) as an array

```js
{
  success: boolean, // true if the operation was successful, false otherwise
  meta: {
    served_by: string // the version of Cloudflare's backend Worker that returned the result
    duration: number, // the duration of the SQL query execution only, in milliseconds
    changes: number, // the number of changes made to the database
    last_row_id: number, // the last inserted row ID, only applies when the table is defined without the `WITHOUT ROWID` option
    changed_db: boolean, // true if something on the database was changed
    size_after: number, // the size of the database after the query is successfully applied
    rows_read: number, // the number of rows read (scanned) by this query
    rows_written: number // the number of rows written by this query
  }
  results: array | null, // [] if empty, or null if it does not apply
}
```

### Example

```js
const someVariable = `Bs Beverages`;
const stmt = env.DB.prepare("SELECT * FROM Customers WHERE CompanyName = ?").bind(someVariable);
const returnValue = await stmt.run();
return Response.json(returnValue)
```

```js
{
  "success": true,
  "meta": {
    "served_by": "miniflare.db",
    "duration": 1,
    "changes": 0,
    "last_row_id": 0,
    "changed_db": false,
    "size_after": 8192,
    "rows_read": 4,
    "rows_written": 0
  },
  "results": [
    {
      "CustomerId": 11,
      "CompanyName": "Bs Beverages",
      "ContactName": "Victoria Ashworth"
    },
    {
      "CustomerId": 13,
      "CompanyName": "Bs Beverages",
      "ContactName": "Random Name"
    }
  ]
}
```

## `D1ExecResult`

The method [`D1Database::exec`](https://developers.cloudflare.com/d1/worker-api/d1-database/#exec) returns a typed [`D1ExecResult`](#d1execresult) object for each query statement. This object contains:

* The number of executed queries
* The duration of the operation in milliseconds

```js
{
  "count": number, // the number of executed queries
  "duration": number // the duration of the operation, in milliseconds
}
```

### Example

```js
const returnValue = await env.DB.exec(`SELECT * FROM Customers WHERE CompanyName = "Bs Beverages"`);
return Response.json(returnValue);
```

```js
{
  "count": 1,
  "duration": 1
}
```

Storing large numbers

Any numeric value in a column is affected by JavaScript's 52-bit precision for numbers. If you store a very large number (in `int64`), then retrieve the same value, the returned value may be less precise than your original number.
