# interval_trigger

<br />

> This page refers to the `interval_trigger` parameter that is part of a [derived_table](https://docs.cloud.google.com/looker/docs/reference/param-view-derived-table).
>
> `interval_trigger` can also be used as part of a datagroup, described on the [`datagroup`](https://docs.cloud.google.com/looker/docs/reference/param-model-datagroup#interval_trigger) parameter documentation page.

## Usage

```
view: my_view {
  derived_table: {
    interval_trigger: "N (seconds | minutes | hours)"
    ...
  }
}
```

|---|---|
| Hierarchy [View File](https://docs.cloud.google.com/looker/docs/reference/param-view) [`view`](https://docs.cloud.google.com/looker/docs/reference/param-view-view) [`derived_table`](https://docs.cloud.google.com/looker/docs/reference/param-view-derived-table) `interval_trigger` | Default Value none <br /> Accepts A string containing an integer followed by a timeframe (seconds, minutes, or hours) |

## Definition

`interval_trigger` lets you trigger the regeneration of a [persistent derived table](https://docs.cloud.google.com/looker/docs/derived-tables#persistent_derived_tables_(pdts)) based on a time interval. In the `interval_trigger` parameter you pass a string containing an integer followed by "seconds", "minutes", or "hours".

## Example

This persistent derived table has an `interval_trigger` of `"3 hours"`, so every three hours it will be triggered to rebuild:

    derived_table: {
      interval_trigger: "3 hours"
      ...
       }
     }