# data-set-unknown

The request names a **data set that SynthEvents does not offer**.

- **Status:** `422 Unprocessable Entity`
- **Route:** `QUERY /api/v1/read-data-set`
- **Description:** `data set is unknown: expected the name of a data set that read-domains lists`
- **Details:** **`value`**, the name as the request gave it.

## Why It Happens

The value of `name` is none of the ready-made data sets. A name is made of the domain, the scenario, and the size, such as `library-everyday-medium`, in lowercase and exactly as **[`read-domains`](/docs/synthevents/api#reading-domains)** lists it, so `library-everyday-huge` and `Library-Everyday-Medium` are unknown.

## How to Fix It

Use the name of one of the data sets that `read-domains` lists. For a range, a size, or a seed that no ready-made data set has, see **[Generating Events](/docs/synthevents/api#generating-events)**.

## Example

For the name `library-everyday-huge`, SynthEvents answers:

```json
{
  "type": "error",
  "data": {
    "code": "https://docs.synthevents.io/errors/data-set-unknown",
    "description": "data set is unknown: expected the name of a data set that read-domains lists",
    "details": {
      "value": "library-everyday-huge"
    }
  }
}
```