> ## 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.

# ExternalContainerPropertyDoesNotExist validation rule

> Validates that any container property referenced by a view property, when the referenced container does not belong to the data model's space, exists in CDF.

This rule checks that, for each view property that maps to a container in a different space than the data model,
the referenced container property exists in that external container in CDF.
This rule only runs if the external container exists in CDF.

## Why it matters

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

## Example

View `my_space:WindTurbine` has a property `location` that maps to container property
`gpsCoordinates` in `other_space:WindTurbineContainer`. If `gpsCoordinates` does not exist
in that container in CDF, deployment will fail.

## Further reading

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