> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cognite.com/llms.txt
> Use this file to discover all available pages before exploring further.

# RequiredContainerDoesNotExist validation rule

> Validates that any container required by another container exists in the data model.

This rule checks that, for each container in the data model, any container it
requires (via requires constraints) exists either in the data model or in CDF.

## Why it matters

If a container requires another container that does not exist in the data model or in CDF,
the data model cannot be deployed. The affected container will not function, and
the deployment of the entire data model will fail.

## Example

Container `windy_space:WindTurbineContainer` has a constraint requiring `windy_space:LocationContainer`.
If `windy_space:LocationContainer` does not exist in the data model or in CDF, deployment will fail.

## Further reading

* [Validation rules](/cdf/deploy/neat/validation/index)