> ## 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.

# ReverseConnectionSourcePropertyMissing validation rule

> Validates that the direct connection property referenced in a reverse connection's 'through' clause exists in the source view.

This rule checks that the direct connection property in the source view (used in the reverse connection's 'through')
actually exists in the source view.

## Why it matters

A reverse connection requires a corresponding direct connection property in the source view.
If this property doesn't exist, the bidirectional connection is incomplete.

## Example

If `WindFarm` has a reverse property `turbines` through `WindTurbine.windFarm`,
but the `WindTurbine` view doesn't have a `windFarm` property, the reverse connection is invalid.

## Further reading

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