# `data.lifecycle_value`

Lifecycle sets a value that isn't fixed.

Area 5, [Data](../topics/data.md); not declinable; the next step is usually the agent's.

A transition sets each field to a fixed value, the same every time it runs:

```jadpo
entity Todo {
    id: Uuid
    deleted_at: Instant?
    edited_at: Instant?

    lifecycle: {
        visible: deleted_at == none
        transitions: {
            delete: {
                set: {
                    deleted_at: edited_at
                }
            }
        }
    }
}
```

```text
error: `edited_at` is another field of the record
 --> main.jadpo:11:33
   |
11 |                     deleted_at: edited_at
   |                                 ^^^^^^^^^ a field, not a value
  reason: A transition sets each field to a fixed value (a literal, an enum value, `none` or `clock.now`), the same every time it runs; copying one field into another isn't one.
  next: Use a literal, an enum value, `none` or `clock.now` (agent)
  rule: data.lifecycle_value
  help: https://jadpo.dev/docs/errors/data.lifecycle_value

check failed: 1 error, 1 file
```