# subject-missing

The request leaves out a **[subject](/docs/eventsourcingdb/subjects)**.

- **Routes:** `write-events`, `read-events`, `observe-events`, and `read-subjects`
- **Description:** `subject is missing: expected a slash-separated path such as '/books/42'`
- **Details:** When writing events, **`event`** or **`precondition`**, the place of the event or the precondition in its list, counting from 0. On the other routes, none; `details` is an empty object.

## Why It Happens

Every event has a subject, and reading events, observing them, and reading subjects start from one. The database reports this error when **`subject` is left out or is an empty string**: at the top level of a read, an observation, or a listing of subjects, in an event of a write, or in the `payload` of an `isSubjectPristine`, `isSubjectPopulated`, or `isSubjectOnEventId` **[precondition](/docs/eventsourcingdb/preconditions)**.

A typical cause is a read that leaves out the subject to get every event. That takes the **root subject `/`** with `recursive` set, see **[Reading All Events](/docs/eventsourcingdb/subjects#reading-all-events)**. A **`fromLatestEvent`** without its subject is reported as **[`from-latest-event-incomplete`](/docs/eventsourcingdb/errors/from-latest-event-incomplete)** instead.

## How to Fix It

Send the subject as a slash-separated path, such as `/books/42`, or as `/` together with `recursive` to cover every subject. Sending the same request again fails the same way, since the error depends on the request alone.

## Example

For a write whose second event leaves out its subject, EventSourcingDB answers with this error, as a line of the stream, and then ends the stream with its `end` item:

```json
{
  "type": "error",
  "data": {
    "code": "https://docs.eventsourcingdb.io/errors/subject-missing",
    "description": "subject is missing: expected a slash-separated path such as '/books/42'",
    "details": {
      "event": 1
    }
  }
}
```